After graduating from Baylor University in 1993, she got an internship with Late Night with Conan O'Brien, working for Max Weinberg. She then moved to Los Angeles and took improvisation classes with The Groundlings and at iO WEST (formerly known as "Improv Olympic West").

Following a one-woman show at iO, she was an operator at 1-800-Dentist and made small one-episode appearances in various sitcoms. She voiced the character "Angela" on two episodes of King of the Hill. In early 2005, she auditioned for the role of receptionist Pam Beesly for the American version of The Office. After producers told her she was "a little too feisty for Pam", she was called back to audition for the role of Angela Martin, which she won. In June 2007, Kinsey shared in the Daytime Emmy Award "Outstanding Broadband Program - Comedy", for her work on The Office: Accountants, which is a series of webisodes.

Kinsey is one of several cast members of The Office to have a role in License to Wed, a fi