She was Miss Kansas 1972 and was a Top 10 finalist and preliminary swimsuit winner at the Miss America 1973 pageant. In 1979 she co-starred in the short-lived series Big Shamus, Little Shamus, with Brian Dennehy, but her breakthrough role was as Dr. Annie Cavanero in the series St. Elsewhere, a role she played for the show's first three seasons.
In 1976, she co-starred in one episode of the TV series Columbo, playing the role of "Della" (daughter of "the Great Santini") in the episode Now You See Him.... She also played a judge in the television series LA Law and co-starred with Burt Reynolds as "Courtney" in the 1983 movie The Man Who Loved Women, which also starred Julie Andrews.
In addition, Sikes appeared on the CBS series Magnum, P.I., which starred Tom Selleck, during the 1980s, and in the feature film Good-bye, Cruel World and Arthur 2: On The Rocks; in the latter, which was a critical and commercial failure, she took over the role of Susan Johnson that Jill Eikenberry had originated in the original Arthur. In the fifth and sixth seasons of JAG, she played the love interest of Adm. Albert Jethro 'A.J.' Chegwidden (played by John M. Jackson).
In 2008, Sikes appeared in The Young and the Restless as Zara, the mother of Sabrina Costelana.
