Colby started her acting career in the theater. Following a performance in
Six Characters in Search of an Author in 1964, she moved to Broadway with a debut in
The Devils the following year. Throughout the rest of the decade, she appeared in such plays as
Under Milk Wood,
Murder in the Cathedral,
Dear Liar and ''
A Doll's House and garnered fine reviews for her Portia in Julius Caesar'' in 1966. Her first important television role was in the first season of
Columbo in an episode titled "Murder by the Book" in 1971. She played many support/guest roles on such established shows as
The Odd Couple,
McMillan & Wife,
The F.B.I.,
Medical Center,
Kung Fu and
Gunsmoke. Colby was a leading actor in the American Conservatory Theater in San Francisco for two years. She appeared in 1970s plays such as
Aubrey Beardsley the Neophyte,
House of Blue Leaves,
Afternoon Tea and
The Hot l Baltimore. She returned to the classics with an off-Broadway role as Elizabeth in
Richard III and was back on Broadway with the plays
Murderous Angels in 1971 and a revival of ''A Doll's House'' in 1975. In 1974, Colby appeared in two films,
California Split and
Memory of Us. In 1975, she had a supporting role in
Rafferty and the Gold Dust Twins. A role as a streetwise prostitute in an episode of
The Mary Tyler Moore Show led to an appearance in a subsequent episode. In 1975, Colby appeared as a new regular player on the
Mary Tyler Moore Show spin-off
Phyllis, starring
Cloris Leachman. Colby, who had appeared with Leachman in the TV movie
A Brand New Life in 1973, was cast as Leachman's boss, Julie Erskine, the owner of a commercial photography studio. ==Personal life==