Matthews coached 22 seasons in the CFL, appeared in nine Grey Cup and won five of them despite crippling anxiety and depression.
The 72-year-old admitted he felt anxious prior to his speech at Friday morning's induction breakfast in Calgary.
"I had to fight it off this morning, so I could do what I did," Matthews said after unveiling his Hall of Fame bust in the afternoon. "When I got up this morning, I didn't know if I was going to vomit. That's what it feels like, like you're on the border-line of nausea and it's swooping over your body
"It was hard for me to get up there and do it, but once I started doing it, I was OK."
Matthews was a fierce and prickly coach who says he drew attention to himself when he felt his players needed protection. Turning himself into a lightning rod for his teams probably didn't help his condition, which reared its head after Matthews turned 60.
"It ended my career," Matthews stated. "It got to the point where I could not do that job any more. I had a long run. I was in my late 60s when I succumbed to the fact that I couldn't do it anymore, but that's a long run in anybody's book."
Matthews was inducted as a builder in the class of 2011 alongside the late Gino Fracas, a University of Windsor coach. Quarterback Danny McManus, defensive end Joe Montford, receiver Terry Vaughn, linebacker Ken Lehmann and Canadian university star Chris Flynn were the players who entered the hall Friday.
Matthews had a panic attack following his first Grey Cup win with the B.C. Lions in 1985. During the post-game celebrations and interviews on the field, he ordered those around him to give him space.
"People thought I was being disrespectful to the crowd, but I was just being surrounded by people and that was scaring me," he said.
The demands of 50 football players became too much for Matthews in Montreal, where he coached from 2002 to 2006.
"I did fight it for a long time," Matthews said. "It got worse until I couldn't do my job. I couldn't go out of the house. I had to force myself to go to work and as soon as work was over I ran back to the house because I just didn't want to be out in public."
Despite his mental-health struggles, the former U.S. marine coached six different CFL clubs, including three separate stints with the Toronto Argonauts. He won back-to-back titles with the Argos in 1996 and 1997.
Matthews had a knack for identifying players who could succeed in the CFL.
"He's one of the guys that, without him, maybe I wouldn't be up here," said Vaughn, who had Matthews as a coach for two seasons with the Eskimos. "He put me on the right path and saw something in me and inspired me."
Matthews sought help for his condition during his time with the Alouettes. After he resigned from the Als in 2006, he went public with the reason why he left. Matthews coached the Argos again for one season in 2008.
"I exposed myself on my depression and anxiety at that point and got a wonderful response from people all over the country of Canada who saw the interview and told me they now don't feel that depression is something that's in the closet and they don't have to be ashamed of it," Matthews said.
"It's an illness and it certainly can be cured. I think something could came out of it. I really feel good about that.
Matthews manages his condition with medication and the support of family. "The Don", as he was called in the CFL, jokingly rubbed the bald head of his bust and circulated with the other inductees Friday.
"This is a little bit different in that it's family," Matthews said. "My three sons are here, my wife is here and her little boy. It's a lot easier. It's not a stressful time.
"Right now, it's pretty easy to be able to deal with this stuff, because this is the rainbow at the end. It'll never be gone forever, but you've got to try and live your life with as little of it as you can and then you'll have a happier life."
He urges those who also suffer anxiety and depression not to give up.
"Modern medicine has made huge strides in trying to help people with this disease," Matthews said. "What works for me is not necessarily going to work for you or somebody else, but there is something out there for you so if you keep looking, you'll find it and it will make you feel an awful lot better."
Note to readers: A previous version of this story referred to the "CFL's Hall of Fame". It has been corrected to "Canadian Football Hall of Fame".