A native of Asheville, North Carolina, Hemphill moved to Los Angeles in the 1970s to pursue a career as a stand-up comedian.

After working the Los Angeles comedy club circuit, her routine eventually attracted attention leading to her being cast in guest starring roles on television.

After the show's cancellation, Hemphill returned to stand-up comedy and also made occasional appearances in films and television until her death in December 1999.

[3][4] By 1976, Hemphill's stand-up routine started to get noticed and caught the attention of casting agent Joan Murray.

[3] Loosely based on Eric Monte's 1975 film Cooley High, the series follows the adventures of three teenaged boys: Raj (Ernest Thomas), Rerun (Fred Berry), and Dwayne (Haywood Nelson).

[5] In the series' second season, Fred Berry and Ernest Thomas staged a walkout over conditions in their dressing rooms which they said were unsuitable.

[5] During the series' third season, Fred Berry demanded more money and reportedly convinced Ernest Thomas and Haywood Nelson to join him in a strike.

[7] On the series, she portrayed Shirley Simmons, a taxi driver who inherited a huge corporation and fortune from one of her customers.

[9] Afterward Hemphill spent most of the early 1980s working in nightclubs around the U.S. and making occasional guest appearances on TV shows, including The Love Boat and Trapper John, M.D..

ended its three-year run, she again worked the nightclub scene and doing the occasional acting gig on a number of '90s comedy sitcoms, including Martin and The Wayans Bros..[9] In 1993, she appeared in her first movie, CB4 which starred Chris Rock.