Mark Shera was born and raised in Bayonne, New Jersey. He attended Boston University and graduated in May 1971 with a BFA in acting. In December of 1971 he was back in Boston and for nine months appeared in the Boston production of "Godspell" He then joined the New York production in the role of "Jesus" After 4 months, he began touring the country in "Godspell". While on tour he was spotted by a Hollywood producer and invited to be in the pilot for a tv show "Nicky's World. The pilot for Nicky's World debuted on April 19, 1974 and even though the show was not a success, someone from the show "Kojak" saw Mark in it and offered him a guest starring role on an episode of "Kojak" Other guest starring roles followed and eventually Mark was cast in the tv show "S.W.A.T. as "Officer Dominic Luca", a role for which most people associate him with. After the cancellation of S.W.A.T., Mark moved over to the tv show "Barnaby Jones" and created the other role that he is known for playing. Mark played the character of "Jedediah (J.R.) Jones for the last four seasons of Barnaby Jones.
While starring on "Barnaby Jones", Mark recorded songs for Capitol Records. One of the songs he recorded in 1979 was titled "Morning Girl". His best selling record in Europe was titled "Girl You'll Be A Star".
In the 80's and early 90's Mark made various guest appearances on tv shows. He starred in the CBS unsold pilot "Adam's House", a comedy that aired on July 14, 1983. He also starred in the ABC unsold pilot "The Ladies of Sweat Street" with Doris Roberts in the spring of 1990.