diff --git a/Sources/ContainerCommands/Container/ContainerKill.swift b/Sources/ContainerCommands/Container/ContainerKill.swift
index ef95a6d1..b223b9ff 100644
--- a/Sources/ContainerCommands/Container/ContainerKill.swift
+++ b/Sources/ContainerCommands/Container/ContainerKill.swift
@@ -61,12 +61,10 @@ extension Application {
                 containers = containerIds
             }
 
-            let signalNumber = try Signal(signal).rawValue
-
             var errors: [any Error] = []
             for container in containers {
                 do {
-                    try await client.kill(id: container, signal: signalNumber)
+                    try await client.kill(id: container, signal: signal)
                     print(container)
                 } catch {
                     errors.append(error)
diff --git a/Sources/Services/ContainerAPIService/Client/ContainerClient.swift b/Sources/Services/ContainerAPIService/Client/ContainerClient.swift
index 291e8cf2..b1b64a66 100644
--- a/Sources/Services/ContainerAPIService/Client/ContainerClient.swift
+++ b/Sources/Services/ContainerAPIService/Client/ContainerClient.swift
@@ -158,12 +158,12 @@ public struct ContainerClient: Sendable {
     }
 
     /// Send a signal to the container.
-    public func kill(id: String, signal: Int32) async throws {
+    public func kill(id: String, signal: String) async throws {
         do {
             let request = XPCMessage(route: .containerKill)
             request.set(key: .id, value: id)
             request.set(key: .processIdentifier, value: id)
-            request.set(key: .signal, value: Int64(signal))
+            request.set(key: .signal, value: signal)
 
             try await xpcClient.send(request)
         } catch {
diff --git a/Sources/Services/ContainerAPIService/Server/Containers/ContainersService.swift b/Sources/Services/ContainerAPIService/Server/Containers/ContainersService.swift
index 82726850..834b31bb 100644
--- a/Sources/Services/ContainerAPIService/Server/Containers/ContainersService.swift
+++ b/Sources/Services/ContainerAPIService/Server/Containers/ContainersService.swift
@@ -547,7 +547,7 @@ public actor ContainersService {
     }
 
     /// Send a signal to the container.
-    public func kill(id: String, processID: String, signal: Int64) async throws {
+    public func kill(id: String, processID: String, signal: String) async throws {
         log.debug(
             "ContainersService: enter",
             metadata: [
@@ -571,6 +571,13 @@ public actor ContainersService {
         let state = try self._getContainerState(id: id)
         let client = try state.getClient()
         try await client.kill(processID, signal: signal)
+
+        // SIGKILL is guaranteed to terminate the target. When directed at the
+        // container's init process, follow up with the same API-server cleanup
+        // that `stop` performs.
+        if processID == id, (try? Signal(signal)) == .kill {
+            try await handleContainerExit(id: id)
+        }
     }
 
     /// Stop all containers inside the sandbox, aborting any processes currently
@@ -1123,8 +1130,11 @@ public actor ContainersService {
 }
 
 extension XPCMessage {
-    func signal() throws -> Int64 {
-        self.int64(key: .signal)
+    func signal() throws -> String {
+        guard let signal = self.string(key: .signal) else {
+            throw ContainerizationError(.invalidArgument, message: "missing signal in xpc message")
+        }
+        return signal
     }
 
     func stopOptions() throws -> ContainerStopOptions {
diff --git a/Sources/Services/Runtime/RuntimeClient/RuntimeClient.swift b/Sources/Services/Runtime/RuntimeClient/RuntimeClient.swift
index 3040902d..087a8120 100644
--- a/Sources/Services/Runtime/RuntimeClient/RuntimeClient.swift
+++ b/Sources/Services/Runtime/RuntimeClient/RuntimeClient.swift
@@ -195,7 +195,7 @@ extension RuntimeClient {
         }
     }
 
-    public func kill(_ id: String, signal: Int64) async throws {
+    public func kill(_ id: String, signal: String) async throws {
         let request = XPCMessage(route: RuntimeRoutes.kill.rawValue)
         request.set(key: RuntimeKeys.id.rawValue, value: id)
         request.set(key: RuntimeKeys.signal.rawValue, value: signal)
diff --git a/Sources/Services/RuntimeLinux/Server/RuntimeService.swift b/Sources/Services/RuntimeLinux/Server/RuntimeService.swift
index a84fd21d..b320d581 100644
--- a/Sources/Services/RuntimeLinux/Server/RuntimeService.swift
+++ b/Sources/Services/RuntimeLinux/Server/RuntimeService.swift
@@ -554,11 +554,13 @@ public actor RuntimeService {
         self.log.debug("enter", metadata: ["func": "\(#function)"])
         defer { self.log.debug("exit", metadata: ["func": "\(#function)"]) }
 
-        return try await self.lock.withLock { [self] _ in
+        let id = try message.id()
+        let signal = try Signal(message.signal())
+
+        try await self.lock.withLock { [self] _ in
             switch await self.state {
             case .running:
                 let ctr = try await getContainer()
-                let id = try message.id()
                 if id != ctr.container.id {
                     guard let processInfo = await self.processes[id] else {
                         throw ContainerizationError(.invalidState, message: "process \(id) does not exist")
@@ -567,13 +569,11 @@ public actor RuntimeService {
                     guard let proc = processInfo.process else {
                         throw ContainerizationError(.invalidState, message: "process \(id) not started")
                     }
-                    try await proc.kill(Signal(rawValue: Int32(try message.signal())))
-                    return message.reply()
+                    try await proc.kill(signal)
+                    return
                 }
 
-                // TODO: fix underlying signal value to int64
-                try await ctr.container.kill(Signal(rawValue: Int32(try message.signal())))
-                return message.reply()
+                try await ctr.container.kill(signal)
             default:
                 throw ContainerizationError(
                     .invalidState,
@@ -581,6 +581,16 @@ public actor RuntimeService {
                 )
             }
         }
+
+        // SIGKILL is guaranteed by the kernel to terminate the target, so block
+        // until we observe the exit.
+        if signal == .kill {
+            _ = await withCheckedContinuation { cc in
+                self.waitForExit(id: id, cont: cc)
+            }
+        }
+
+        return message.reply()
     }
 
     /// Resize the terminal for a process.
@@ -1252,8 +1262,11 @@ public actor RuntimeService {
 }
 
 extension XPCMessage {
-    fileprivate func signal() throws -> Int64 {
-        self.int64(key: RuntimeKeys.signal.rawValue)
+    fileprivate func signal() throws -> String {
+        guard let signal = self.string(key: RuntimeKeys.signal.rawValue) else {
+            throw ContainerizationError(.invalidArgument, message: "missing signal in xpc message")
+        }
+        return signal
     }
 
     fileprivate func stopOptions() throws -> ContainerStopOptions {