diff --git a/docs/roadmap.md b/docs/roadmap.md
index 561a8a2..3f6e25b 100644
--- a/docs/roadmap.md
+++ b/docs/roadmap.md
@@ -57,6 +57,30 @@
 
 ---
 
+## Milestone 1.9: Async Refactor
+
+**Goal:** Prepare codebase for concurrent CLI + network operation.
+
+### Deliverables
+
+**Phase 1: Store Actor (sync)** ✓
+- [x] Store actor pattern: dedicated thread owns Store, receives commands via `std::sync::mpsc`
+- [x] StoreHandle wraps channel sender, keeps current API
+- [x] Validate: CLI works as before with actor
+
+**Phase 2: Async Runtime**
+- [ ] Add tokio runtime (`#[tokio::main]`)
+- [ ] Migrate `std::sync::mpsc` → `tokio::sync::mpsc`
+- [ ] Async CLI using `tokio::io::stdin()` or `rustyline` async
+
+### Success Criteria
+
+- [x] CLI still works as before
+- [x] Store operations serialized (no data races)
+- [ ] Ready for concurrent network tasks
+
+---
+
 ## Milestone 2: Two-Node Sync
 
 **Goal:** Two nodes can sync their logs over the network.
@@ -68,6 +92,7 @@
 - [ ] Iroh integration (peer discovery, connection)
 - [ ] Multi-author log merging
 - [ ] CLI: `peers`, `connect`/`join` commands
+- [ ] Background sync task (tokio::spawn)
 
 ### Success Criteria
 
diff --git a/lattice-cli/src/main.rs b/lattice-cli/src/main.rs
index df76338..15123da 100644
--- a/lattice-cli/src/main.rs
+++ b/lattice-cli/src/main.rs
@@ -2,6 +2,7 @@
 
 mod node;
 mod commands;
+mod store_actor;
 
 use commands::CommandResult;
 use node::{LatticeNodeBuilder, StoreHandle};
diff --git a/lattice-cli/src/node.rs b/lattice-cli/src/node.rs
index 99871d2..6c58402 100644
--- a/lattice-cli/src/node.rs
+++ b/lattice-cli/src/node.rs
@@ -1,8 +1,7 @@
 //! Local Lattice node API with multi-store support
 
 use lattice_core::{
-    DataDir, EntryBuilder, MetaStore, Node, SigChain, Store, Uuid,
-    hlc::HLC,
+    DataDir, MetaStore, Node, SigChain, Store, Uuid,
     log::LogError,
     meta_store::MetaStoreError,
     sigchain::SigChainError,
@@ -10,7 +9,6 @@ use lattice_core::{
 };
 use std::path::Path;
 use std::rc::Rc;
-use std::cell::RefCell;
 use thiserror::Error;
 
 #[derive(Error, Debug)]
@@ -35,6 +33,12 @@ pub enum NodeError {
     
     #[error("Already initialized")]
     AlreadyInitialized,
+    
+    #[error("Channel closed")]
+    ChannelClosed,
+    
+    #[error("Actor error: {0}")]
+    Actor(String),
 }
 
 pub struct NodeInfo {
@@ -167,85 +171,101 @@ impl LatticeNode {
         };
         
         let info = StoreInfo { store_id, entries_replayed };
+        
+        // Spawn actor thread - actor owns store, sigchain, and node copy
+        let (tx, actor_handle) = crate::store_actor::spawn_store_actor(
+            store_id,
+            store,
+            sigchain,
+            (*self.node).clone(),
+        );
+        
         let handle = StoreHandle {
             store_id,
-            node: Rc::clone(&self.node),
-            sigchain: RefCell::new(sigchain),
-            store,
+            tx,
+            actor_handle,
         };
         
         Ok((handle, info))
     }
 }
 
-/// A handle to a specific store with KV operations
+/// A handle to a specific store - wraps channel to actor thread
 pub struct StoreHandle {
     store_id: Uuid,
-    node: Rc<Node>,
-    sigchain: RefCell<SigChain>,
-    store: Store,
+    tx: std::sync::mpsc::Sender<crate::store_actor::StoreCmd>,
+    #[allow(dead_code)]
+    actor_handle: std::thread::JoinHandle<()>,
 }
 
 impl StoreHandle {
     pub fn id(&self) -> Uuid { self.store_id }
 
     pub fn get(&self, key: &[u8]) -> Result<Option<Vec<u8>>, NodeError> {
-        Ok(self.store.get(key)?)
+        use crate::store_actor::StoreCmd;
+        let (resp_tx, resp_rx) = std::sync::mpsc::channel();
+        self.tx.send(StoreCmd::Get { key: key.to_vec(), resp: resp_tx })
+            .map_err(|_| NodeError::ChannelClosed)?;
+        resp_rx.recv()
+            .map_err(|_| NodeError::ChannelClosed)?
+            .map_err(NodeError::Store)
     }
 
     pub fn get_heads(&self, key: &[u8]) -> Result<Vec<lattice_core::HeadInfo>, NodeError> {
-        Ok(self.store.get_heads(key)?)
+        use crate::store_actor::StoreCmd;
+        let (resp_tx, resp_rx) = std::sync::mpsc::channel();
+        self.tx.send(StoreCmd::GetHeads { key: key.to_vec(), resp: resp_tx })
+            .map_err(|_| NodeError::ChannelClosed)?;
+        resp_rx.recv()
+            .map_err(|_| NodeError::ChannelClosed)?
+            .map_err(NodeError::Store)
     }
 
     pub fn list(&self) -> Result<Vec<(Vec<u8>, Vec<u8>)>, NodeError> {
-        Ok(self.store.list_all()?)
+        use crate::store_actor::StoreCmd;
+        let (resp_tx, resp_rx) = std::sync::mpsc::channel();
+        self.tx.send(StoreCmd::List { resp: resp_tx })
+            .map_err(|_| NodeError::ChannelClosed)?;
+        resp_rx.recv()
+            .map_err(|_| NodeError::ChannelClosed)?
+            .map_err(NodeError::Store)
     }
 
     pub fn log_seq(&self) -> u64 {
-        self.sigchain.borrow().len()
+        use crate::store_actor::StoreCmd;
+        let (resp_tx, resp_rx) = std::sync::mpsc::channel();
+        let _ = self.tx.send(StoreCmd::LogSeq { resp: resp_tx });
+        resp_rx.recv().unwrap_or(0)
     }
 
     pub fn applied_seq(&self) -> Result<u64, NodeError> {
-        let author = self.node.public_key_bytes();
-        Ok(self.store.author_state(&author)?
-            .map(|s| s.seq)
-            .unwrap_or(0))
+        use crate::store_actor::StoreCmd;
+        let (resp_tx, resp_rx) = std::sync::mpsc::channel();
+        self.tx.send(StoreCmd::AppliedSeq { resp: resp_tx })
+            .map_err(|_| NodeError::ChannelClosed)?;
+        resp_rx.recv()
+            .map_err(|_| NodeError::ChannelClosed)?
+            .map_err(NodeError::Store)
     }
 
     pub fn put(&self, key: &[u8], value: &[u8]) -> Result<u64, NodeError> {
-        // Get current heads for this key to cite as parents
-        let heads = self.store.get_heads(key)?;
-        let parent_hashes: Vec<Vec<u8>> = heads.iter().map(|h| h.hash.clone()).collect();
-        
-        self.commit_entry(parent_hashes, |b| b.put(key.to_vec(), value.to_vec()))
+        use crate::store_actor::StoreCmd;
+        let (resp_tx, resp_rx) = std::sync::mpsc::channel();
+        self.tx.send(StoreCmd::Put { key: key.to_vec(), value: value.to_vec(), resp: resp_tx })
+            .map_err(|_| NodeError::ChannelClosed)?;
+        resp_rx.recv()
+            .map_err(|_| NodeError::ChannelClosed)?
+            .map_err(|e| NodeError::Actor(e.to_string()))
     }
 
     pub fn delete(&self, key: &[u8]) -> Result<u64, NodeError> {
-        // Get current heads for this key to cite as parents
-        let heads = self.store.get_heads(key)?;
-        let parent_hashes: Vec<Vec<u8>> = heads.iter().map(|h| h.hash.clone()).collect();
-        
-        self.commit_entry(parent_hashes, |b| b.delete(key.to_vec()))
-    }
-
-    fn commit_entry<F>(&self, parent_hashes: Vec<Vec<u8>>, build: F) -> Result<u64, NodeError>
-    where
-        F: FnOnce(EntryBuilder) -> EntryBuilder,
-    {
-        let mut sigchain = self.sigchain.borrow_mut();
-        let seq = sigchain.len() + 1;
-        let prev_hash = sigchain.last_hash();
-        
-        let builder = EntryBuilder::new(seq, HLC::now())
-            .store_id(self.store_id.as_bytes().to_vec())
-            .prev_hash(prev_hash.to_vec())
-            .parent_hashes(parent_hashes);
-        let entry = build(builder).sign(&self.node);
-        
-        sigchain.append(&entry)?;
-        self.store.apply_entry(&entry)?;
-        
-        Ok(seq)
+        use crate::store_actor::StoreCmd;
+        let (resp_tx, resp_rx) = std::sync::mpsc::channel();
+        self.tx.send(StoreCmd::Delete { key: key.to_vec(), resp: resp_tx })
+            .map_err(|_| NodeError::ChannelClosed)?;
+        resp_rx.recv()
+            .map_err(|_| NodeError::ChannelClosed)?
+            .map_err(|e| NodeError::Actor(e.to_string()))
     }
 }
 
diff --git a/lattice-cli/src/store_actor.rs b/lattice-cli/src/store_actor.rs
new file mode 100644
index 0000000..af5d49e
--- /dev/null
+++ b/lattice-cli/src/store_actor.rs
@@ -0,0 +1,189 @@
+//! Store Actor - dedicated thread that owns Store and processes commands via channel
+
+use lattice_core::{
+    EntryBuilder, HeadInfo, Node, SigChain, Store, Uuid,
+    hlc::HLC,
+    proto::AuthorState,
+    sigchain::SigChainError,
+    store::StoreError,
+};
+use std::sync::mpsc::{self, Receiver, Sender};
+use std::thread::{self, JoinHandle};
+
+/// Commands sent to the store actor
+pub enum StoreCmd {
+    Get {
+        key: Vec<u8>,
+        resp: std::sync::mpsc::Sender<Result<Option<Vec<u8>>, StoreError>>,
+    },
+    GetHeads {
+        key: Vec<u8>,
+        resp: std::sync::mpsc::Sender<Result<Vec<HeadInfo>, StoreError>>,
+    },
+    List {
+        resp: std::sync::mpsc::Sender<Result<Vec<(Vec<u8>, Vec<u8>)>, StoreError>>,
+    },
+    Put {
+        key: Vec<u8>,
+        value: Vec<u8>,
+        resp: std::sync::mpsc::Sender<Result<u64, StoreActorError>>,
+    },
+    Delete {
+        key: Vec<u8>,
+        resp: std::sync::mpsc::Sender<Result<u64, StoreActorError>>,
+    },
+    LogSeq {
+        resp: std::sync::mpsc::Sender<u64>,
+    },
+    AppliedSeq {
+        resp: std::sync::mpsc::Sender<Result<u64, StoreError>>,
+    },
+    AuthorState {
+        author: [u8; 32],
+        resp: std::sync::mpsc::Sender<Result<Option<AuthorState>, StoreError>>,
+    },
+    Shutdown,
+}
+
+#[derive(Debug)]
+pub enum StoreActorError {
+    Store(StoreError),
+    SigChain(SigChainError),
+    ChannelClosed,
+}
+
+impl From<StoreError> for StoreActorError {
+    fn from(e: StoreError) -> Self {
+        StoreActorError::Store(e)
+    }
+}
+
+impl From<SigChainError> for StoreActorError {
+    fn from(e: SigChainError) -> Self {
+        StoreActorError::SigChain(e)
+    }
+}
+
+impl std::fmt::Display for StoreActorError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            StoreActorError::Store(e) => write!(f, "Store error: {}", e),
+            StoreActorError::SigChain(e) => write!(f, "SigChain error: {}", e),
+            StoreActorError::ChannelClosed => write!(f, "Channel closed"),
+        }
+    }
+}
+
+impl std::error::Error for StoreActorError {}
+
+/// The store actor - runs in its own thread, owns Store and SigChain
+pub struct StoreActor {
+    store_id: Uuid,
+    store: Store,
+    sigchain: SigChain,
+    node: Node,
+    rx: Receiver<StoreCmd>,
+}
+
+impl StoreActor {
+    /// Create a new store actor (but don't start the thread yet)
+    pub fn new(
+        store_id: Uuid,
+        store: Store,
+        sigchain: SigChain,
+        node: Node,
+        rx: Receiver<StoreCmd>,
+    ) -> Self {
+        Self {
+            store_id,
+            store,
+            sigchain,
+            node,
+            rx,
+        }
+    }
+
+    /// Run the actor loop - processes commands until Shutdown received
+    pub fn run(mut self) {
+        while let Ok(cmd) = self.rx.recv() {
+            match cmd {
+                StoreCmd::Get { key, resp } => {
+                    let _ = resp.send(self.store.get(&key));
+                }
+                StoreCmd::GetHeads { key, resp } => {
+                    let _ = resp.send(self.store.get_heads(&key));
+                }
+                StoreCmd::List { resp } => {
+                    let _ = resp.send(self.store.list_all());
+                }
+                StoreCmd::Put { key, value, resp } => {
+                    let result = self.do_put(&key, &value);
+                    let _ = resp.send(result);
+                }
+                StoreCmd::Delete { key, resp } => {
+                    let result = self.do_delete(&key);
+                    let _ = resp.send(result);
+                }
+                StoreCmd::LogSeq { resp } => {
+                    let _ = resp.send(self.sigchain.len());
+                }
+                StoreCmd::AppliedSeq { resp } => {
+                    let author = self.node.public_key_bytes();
+                    let result = self.store.author_state(&author)
+                        .map(|s| s.map(|a| a.seq).unwrap_or(0));
+                    let _ = resp.send(result);
+                }
+                StoreCmd::AuthorState { author, resp } => {
+                    let _ = resp.send(self.store.author_state(&author));
+                }
+                StoreCmd::Shutdown => {
+                    break;
+                }
+            }
+        }
+    }
+
+    fn do_put(&mut self, key: &[u8], value: &[u8]) -> Result<u64, StoreActorError> {
+        let heads = self.store.get_heads(key)?;
+        let parent_hashes: Vec<Vec<u8>> = heads.iter().map(|h| h.hash.clone()).collect();
+        self.commit_entry(parent_hashes, |b| b.put(key.to_vec(), value.to_vec()))
+    }
+
+    fn do_delete(&mut self, key: &[u8]) -> Result<u64, StoreActorError> {
+        let heads = self.store.get_heads(key)?;
+        let parent_hashes: Vec<Vec<u8>> = heads.iter().map(|h| h.hash.clone()).collect();
+        self.commit_entry(parent_hashes, |b| b.delete(key.to_vec()))
+    }
+
+    fn commit_entry<F>(&mut self, parent_hashes: Vec<Vec<u8>>, build: F) -> Result<u64, StoreActorError>
+    where
+        F: FnOnce(EntryBuilder) -> EntryBuilder,
+    {
+        let seq = self.sigchain.len() + 1;
+        let prev_hash = self.sigchain.last_hash();
+
+        let builder = EntryBuilder::new(seq, HLC::now())
+            .store_id(self.store_id.as_bytes().to_vec())
+            .prev_hash(prev_hash.to_vec())
+            .parent_hashes(parent_hashes);
+        let entry = build(builder).sign(&self.node);
+
+        self.sigchain.append(&entry)?;
+        self.store.apply_entry(&entry)?;
+
+        Ok(seq)
+    }
+}
+
+/// Spawn a store actor in a new thread, returns (sender, join_handle)
+pub fn spawn_store_actor(
+    store_id: Uuid,
+    store: Store,
+    sigchain: SigChain,
+    node: Node,
+) -> (Sender<StoreCmd>, JoinHandle<()>) {
+    let (tx, rx) = mpsc::channel();
+    let actor = StoreActor::new(store_id, store, sigchain, node, rx);
+    let handle = thread::spawn(move || actor.run());
+    (tx, handle)
+}
diff --git a/lattice-core/src/node.rs b/lattice-core/src/node.rs
index 8c22bfb..96958cc 100644
--- a/lattice-core/src/node.rs
+++ b/lattice-core/src/node.rs
@@ -28,6 +28,7 @@ pub enum NodeError {
 ///
 /// Each node has an Ed25519 keypair used for signing sigchain entries
 /// and establishing trust within the network.
+#[derive(Clone)]
 pub struct Node {
     signing_key: SigningKey,
 }