Clair died in Sarasota, Fla. He was 87.
After leading the Toronto Argonauts to two Grey Cup titles in the early 1950s, Clair joined the Riders in 1956 and started to turn around the poorly-run organization.
Under his coaching guidance, the Riders won the Grey Cup in 1960, 1968 and 1969.
Former Ottawa Rough Riders coach Frank Clair passed away on Sunday. (CP File Photo)
He retired from coaching with his name attached to nearly every CFL record. Only Montreal's Don Matthews (230 victories) and B.C.'s Wally Buono (193) have more career coaching wins in CFL history than Clair's 147.
He took over the general manager's role in 1970 and once again found success, leading the Riders to championships in 1973 and 1976.
He was released after the 1978 season and Ottawa hasn't come close to a Grey Cup title since his departure.
Clair was inducted into the CFL Hall of Fame as a builder in 1981.
Lansdowne Park, home of the CFL's Ottawa Renegades and former stadium of the Rough Riders, was renamed in Clair's honour in 1993.