MARS CALLAHAN Date of Birth: c. 1972 Mars Callahan started out in show business as a child actor called Gregory Martin. He played guest appearances on TV shows such as Growing Pains, Knots Landing and The Wonder Years, and was nominated for a Young Artist award for his role in the TV movie The Children of Times Square (1986). At 20, he was credited as Gregory Mars Martin for his role in the film Highway to Hell (1992), and when he played a small role in Kalifornia (1993) the following... See All