With the advance of various wireless access technologies, the demand for a mobile user equipped with multiple air interfaces simultaneously executing diverse applications emerged. In such network environment, perapplication mobility management is a key to allow each application of an end user device to dynamically and fully take advantage of the most suitable access technology. In this paper, we devised a comprehensive architectural platform with crosslayer techniques to realize this disruptive technology, i.e., perapplication mobility management. Four core functional modules composing the proposed platform for end user devices are defined: Monitoring Agents, Profile Database, Decision Engine, and IP Agent. We show through simulations that the presented platform provides an improved QoS as it selectively utilizes the best available networks depending on different QoS constraints of different applications.