In 1956, he joined the Canadian Football League (CFL) with the Hamilton Tiger-Cats, helping lead them to a 1957 Grey Cup victory.

Incidentally, Gilchrist was Buffalo's backup plan: they had actually drafted Ernie Davis to be the team's franchise running back in 1962.

Gilchrist ran for 122 yards in the Bills' 1964 American Football League championship defeat of the San Diego Chargers, 20–7.

In an early civil rights victory for black athletes, Gilchrist led a successful boycott of New Orleans as the site of the 1965 American Football League All-Star game.

When he was informed about being nominated by the Hall by John Agro (counsel for the Canadian Football League Players Association), he was told to be "nice" to Jake Gaudaur, the CFL commissioner, and Gilchrist stated that he would "take it under advisement" due to his strained relations with Gaudaur while also expressing the belief that Canada had treated him as a "persona non grata" from 1956 to 2010.

He told a reporter from the London Free Press that most of the problems he encountered were a result of his standing up for principles at a time when black athletes were expected to remain silent.

He was sent to the man who started his career, Paul Brown in the Cincinnati Bengals expansion draft in 1968, but retired because of knee problems.

In 1974, Gilchrist founded the United Athletes Coalition of America to help former football players adjust to life after retirement.

In 1975, he booked Marvin Gaye, Ike & Tina Turner, and Taveres for a benefit concert at Maple Leaf Gardens in Toronto.

It has been stated that he refused entry into the Canadian Football Hall of Fame because he did not believe he was paid well enough for his service, while other sources contend it Gilchrist rejected the honor due to how he was treated in the past.

[14] Gilchrist was aware of the possibility that he had the disease when writing his autobiography, The Cookie That Did Not Crumble, along with Chris Garbarino[citation needed].