Liaison and ancillary franchise member. Recruited by Steve Rogers to coordinate his covert operations with the Mansion and Tower teams in Secret Avengers (1st series) #1. Unlike other liaisons Hill and Hand, she served as a field agent with the team as well.
Sharon Carter was reportedly brainwashed into the service of Doctor Faustus and his National Force, who then all committed suicide due to incendiary devices in their uniforms. Captain America was shown a video of Sharon apparently dying in Captain America (1st series) #237. Years later, in #445, the tape was revealed a fake as Carter had been undercover for years on behalf of Nick Fury on a separate mission.
Sharon Carter has recently aged prematurely after spending a compress amount of time in Dimension Z between Captain America (7th series) #10-25. She later had her youth restored in Captain America (8th series) #23.