diff --git a/mainapp.cpp b/mainapp.cpp
index b9e6121..7751aa9 100644
--- a/mainapp.cpp
+++ b/mainapp.cpp
@@ -72,7 +72,8 @@
     bus.attach_event(eventP.get(), SD_EVENT_PRIORITY_NORMAL);
 
     // Create a watchdog object
-    phosphor::watchdog::Watchdog watchdog(bus, path.c_str(), eventP);
+    phosphor::watchdog::Watchdog watchdog(bus, path.c_str(),
+                                          eventP, std::move(target));
 
     // Claim the bus
     bus.request_name(service.c_str());
diff --git a/watchdog.cpp b/watchdog.cpp
index e5e8aff..99ef679 100644
--- a/watchdog.cpp
+++ b/watchdog.cpp
@@ -9,6 +9,11 @@
 using namespace std::chrono_literals;
 using namespace phosphor::logging;
 
+// systemd service to kick start a target.
+constexpr auto SYSTEMD_SERVICE    = "org.freedesktop.systemd1";
+constexpr auto SYSTEMD_ROOT       = "/org/freedesktop/systemd1";
+constexpr auto SYSTEMD_INTERFACE  = "org.freedesktop.systemd1.Manager";
+
 // Enable or disable watchdog
 bool Watchdog::enabled(bool value)
 {
@@ -94,9 +99,18 @@
 // Optional callback function on timer expiration
 void Watchdog::timeOutHandler()
 {
-    log<level::INFO>("Optional callback called");
-    // TODO: Need to call the user passed systemd
-    // target on this condition
+    if (!target.empty())
+    {
+        auto method = bus.new_method_call(SYSTEMD_SERVICE,
+                                          SYSTEMD_ROOT,
+                                          SYSTEMD_INTERFACE,
+                                          "StartUnit");
+        method.append(target);
+        method.append("replace");
+
+        bus.call_noreply(method);
+    }
+    return;
 }
 
 } // namespace watchdog
diff --git a/watchdog.hpp b/watchdog.hpp
index 1a7a410..79df438 100644
--- a/watchdog.hpp
+++ b/watchdog.hpp
@@ -29,15 +29,18 @@
 
         /** @brief Constructs the Watchdog object
          *
-         *  @param[in] bus     - DBus bus to attach to
-         *  @param[in] objPath - Object path to attach to
+         *  @param[in] bus     - DBus bus to attach to.
+         *  @param[in] objPath - Object path to attach to.
          *  @param[in] event   - reference to sd_event unique pointer
+         *  @param[in] target  - systemd target to be called into on timeout
          */
         Watchdog(sdbusplus::bus::bus& bus,
                 const char* objPath,
-                EventPtr& event) :
+                EventPtr& event,
+                std::string&& target = std::string()) :
             WatchdogInherits(bus, objPath),
             bus(bus),
+            target(std::move(target)),
             timer(event, std::bind(&Watchdog::timeOutHandler, this))
         {
             // Nothing
@@ -83,6 +86,9 @@
         /** @brief sdbusplus handle */
         sdbusplus::bus::bus& bus;
 
+        /** @brief Systemd unit to be started when the timer expires */
+        std::string target;
+
         /** @brief Contained timer object */
         Timer timer;