March is best known for her role as Assistant District Attorney Alexandra Cabot on the NBC crime legal drama series "", a role she played from 2000 to 2003. She departed in the Season 5 episode "Loss", when Cabot is shot and placed in witness protection. She returned to the series for a six-episode arc in Season 10 and then continued as a main character in Season 11. After her departure near the end of Season 11, she returned again in Season 13 as a recurring character. She reprised her role once again in an episode on the show's nineteenth season.