Actress and acting coach Janet Williams Adderley was born Janet Williams in Marshall, Texas, on September 17, 1956. Adderley’s mother, Velma Bernice MacAfee Williams, a mathematics professor, and her father Dr. John L. Williams, an optometrist, raised Adderley in Houston, Texas; Walter MacAfee, the pioneering radio astronomer, was her uncle. Attending Turner Elementary, Edgar Allen Poe Elementary and Holy Spirit Catholic School, Adderley graduated from Houston’s Performing Arts High School in 1974. At Yale University, Adderley was a member of the Yale Dramat (the Yale Dramatic Association) before graduating in 1978 with her B.A. degree in American studies.
Moving to New York City, Adderley married Nat Adderley, Jr., whom she met at Yale University, in 1979, and started a family. Involved in various entertainment classes and projects, Adderley landed the role of Belle in the Broadway production of the Andrew Lloyd Webber musical Starlight Express. In 1990, Adderley was featured in the play A...My Name is Alice and appeared in television commercials in America and Britain. In 1991, Adderley relocated to Hollywood where she appeared in regional theatrical productions. In 1994 and 1995, Adderley appeared in the television series Sweet Justice with Cicely Tyson; she also appeared in the 1999 movie Annie, and I Am Sam in 2001.
In 1994, Adderley started a performing arts class for her daughter and fourteen other children; as the word spread, The Adderley School for the Performing Arts in Pacific Palisades was formed. At The Adderley School, students were instructed in all of the elements of musical theatre by performing youth versions of Broadway shows.