McComb started acting at age two in a commercial for Publisher's Clearing House. Then she appeared in the telefilm Generation X in 1996, she became the first actress to portray the X-Men character of Jubilee on screen. She joined the cast of Party of Five in 1998, playing the part of Maggie.
McComb married actor James Van Der Beek on July 5, 2003. On June 10, 2009, it was confirmed that the couple had separated.