At Beloit College, he acted in student theater productions, and, while living in Washington, D.C., he landed a job with a production of
The Great White Hope at the
Arena Stage and then acted in theatrical productions of
Caligula and
Indians. The
United Artists film received a limited theatrical release and grossed under $1 million. Another film from early in his acting career was the controversial
White Dog (1982). In addition, he played the leads in several
CBS television movies:
Women at West Point (1979),
Anatomy of a Seduction (1979),
The Gathering II (1979),
The Promise of Love (1980),
Callie and Son (1981), and
A Caribbean Mystery (1983). He became well known by co-starring as A.J. Simon in
Simon & Simon from 1981 to 1989. With his
Simon & Simon co-star
Gerald McRaney he appeared in the theatrical movie
Jackals, which Parker co-produced. After completing this movie, he returned to Beloit College to star in a live summer stock theatrical production as Brick in
Cat on a Hot Tin Roof. In 1987, starred alongside
Donald Pleasence in
John Carpenter's horror movie
Prince of Darkness. Parker guest-starred on the
CBS series
Walker, Texas Ranger as a corrupt cop. He appeared in the television movies
Who Is Julia? (1986),
Dead Before Dawn (1993), and
Violation of Trust (1991). He guest starred on the sitcom
Major Dad with his
Simon & Simon co-star Gerald McRaney. Parker's last known acting work was in 2003–2004, after a four-year hiatus, when he appeared in four episodes of
JAG. In 2003, he co-hosted the show ''A Dog's Life
with wife Darleen on the Outdoor Life Network (OLN). In 2009, Parker did voice-over work as the narrator for the documentary Endangered Species: California Fish and Game Wardens''. ==Writing career==