A star player at Har-Brack High School (Natrona Heights, Pa), in 1953 he led the team to the W.P.I.A.L. co-championship with Donora. As a junior, he was talked into signing a professional football contract with the NFL's Cleveland Browns by Paul Brown. The signing was against NFL rules and likely illegal, and when Brown reneged on his promise that Gilchrist would make the team, Gilchrist left training camp at Hiram College, in Hiram, Ohio, and went to Canada to play. There, in the Ontario Rugby Football Union (ORFU), he received the Jim Shanks (Team MVP) Trophy for the Sarnia Imperials in 1954, and the Kitchener-Waterloo Dutchmen's Team MVP Award in 1955.
In 1956, he joined the Canadian Football League (CFL) with the Hamilton Tiger-Cats, helping lead them to a 1957 Grey Cup victory. He spent one season with the Saskatchewan Roughriders, rushing for 1,254 yards. He then was traded to the Toronto Argonauts for Tex Schwierer, and played three years in Toronto.[1] In his six years in the CFL, Gilchrist was a divisional All-Star at running back five consecutive years from 1956 to 1960 (there were no All-Canadians selected in those years) and was also an Eastern All-Star at linebacker in 1960. Additionally, in 1960 he was runner up for the CFL's Most Outstanding Player Award. In his CFL career, Gilchrist recorded 4,911 rushing yards, 1,068 receiving yards and 12 interceptions.