diff --git a/src/sdeventplus/utility/timer.cpp b/src/sdeventplus/utility/timer.cpp
index 242f5d6..638f8e1 100644
--- a/src/sdeventplus/utility/timer.cpp
+++ b/src/sdeventplus/utility/timer.cpp
@@ -44,8 +44,8 @@
                  std::optional<Duration> interval,
                  typename source::Time<Id>::Accuracy accuracy) :
     expired(false),
-    initialized(interval.has_value()), callback(callback), clock(event),
-    interval(interval),
+    initialized(interval.has_value()), callback(std::move(callback)),
+    clock(event), interval(interval),
     timeSource(event, clock.now() + interval.value_or(Duration::zero()),
                accuracy,
                std::bind(&Timer::internalCallback, this, std::placeholders::_1,
diff --git a/src/sdeventplus/utility/timer.hpp b/src/sdeventplus/utility/timer.hpp
index 5d36458..bca5566 100644
--- a/src/sdeventplus/utility/timer.hpp
+++ b/src/sdeventplus/utility/timer.hpp
@@ -1,7 +1,7 @@
 #pragma once
 
 #include <chrono>
-#include <functional>
+#include <function2/function2.hpp>
 #include <optional>
 #include <sdeventplus/clock.hpp>
 #include <sdeventplus/event.hpp>
@@ -35,7 +35,7 @@
     /** @brief Type of the user provided callback function when the
      *         timer elapses.
      */
-    using Callback = std::function<void(Timer<Id>&)>;
+    using Callback = fu2::unique_function<void(Timer<Id>&)>;
 
     Timer(const Timer& other) = delete;
     Timer(Timer&& other);