Born in San Diego, California, she starred on Nickelodeon's All That Sketch comedy show from 1994 to 1997. As part of the show's original cast, she played characters such as the "Lemonade Scammer". She also did impressions of Roseanne Barr and Ross Perot in many episodes. Johnson returned for the 100th episode, along with fellow All That alumni Angelique Bates, Lori Beth Denberg, and Alisa Reyes. She also returned for the All That 10th Anniversary special.