Architecture for seamless role switching in application sharing. A multipoint control unit (MCU) can be used for connecting multiple clients over a network. An application sharing component establishes an application sharing session over the MCU, and application content is exchanged from a sharer client to one or more viewer clients. Each client can communicate a media connection preference to the session. Client sharer and viewer roles are defined during creation of the application sharing session. A client can seamlessly switch roles during the session from a viewer to a sharer, and vice-versa, so that different application content can be shared to the session viewers. The session can be restricted to only one sharer so that the viewing clients view one sharer client at a time.