Tim Kennedy has rolled with the punches for his entire MMA career, which began in 2001 in Oroville, Calif. on the regional circuit, and ended nearly 15 years later in Toronto on the biggest stage. It wasn’t supposed to end the way it did.

Kennedy had hoped to hang up the gloves, win or lose, at Madison Square Garden three weeks earlier against Rashad Evans at UFC 205. That fight was scrapped when Evans failed to clear a medical test beforehand, which sent Kennedy to Canada for a fight with Kelvin Gastelum. He rolled with the punches, though, and ended up losing via third-round TKO (punches).

A month later, at 37 years old and with a record of 18-6, he officially retired from competing in the sport of mixed martial arts, posting a message on his Facebook page. Though the setting wasn’t what he at first envisioned, and the ambulance ride to the hospital afterwards wasn’t the storybook end he’d hoped, he says he knew it was time.

“I knew that the outcome of the fight regardless of a win or a loss was going to be me being retired,” he told MMA Fighting on Tuesday. “There was one or two scenarios that could have maybe kept me around, and that was me fighting Michael Bisping in like, London, for 10 percent of the entire pay-per-view, which is obviously an impossibility.”

Here he laughed, in his Tim Kennedy way of letting his dry joke sink it.

“So, I was done. I knew I was done. I wanted a Cinderella story. I wanted to go out fighting Rashad at Madison Square Garden, but that’s not how life is. So I knew I was going to be done regardless.”

Kennedy faded in the fight with Gastelum, particularly after a first round in which is exerted a lot of energy clinching and trying to take the fight to the canvas. By the second round, he looked tired. He admitted in his retirement letter that his body just wasn’t responded to what his mind was telling him. He battled on, but the fight played out for him as a real-time testament that it was time to get on with the next chapter of his life.

Part of which includes helping spearhead the Mixed Martial Arts Athletes Association (MMAAA) that he and a handful of his fellow fighters launched in November.

“I really pride myself on being intelligent, smart, but most importantly as a man that understands his assets and liabilities,” he said. “Nothing, like, existentialist or anything, but when you are critically evaluating yourself and your performance, you know what you’re supposed to do, but physically you’re not able to do it. If anything, that fight — and more specifically, my performance in that fight — solidified in every single way that I was doing the right thing by walking away from the sport.”

Kennedy, a special forces operator who is still active military, said that in his last fight, which many paid attention to behind the scenes, might produce a cold shoulder from the UFC, given his involvement with the MMAAA. He said that wasn’t the case.

“No, it was actually 100 percent professional and candid and honest,” he said. “At UFC 205, they went out of their way to be accommodating and courteous, like it should be. Not that it was that surprising. I love fighting for the UFC, and I love this sport. I just know that we just need a change, and something needs to happen for the sport to continue.”

In his note, Kennedy wrote that he will devote himself to helping other fighters who will need support at the end of their own careers.

“So with that, to all of you fighters out there, I am not going anywhere,” he wrote. “ I love fighting and will always have the heart of a figher. I am committed to growing our sport and taking care of those who are a part of it. As sad as it is for me to walk away, the only thing sadder would be for me to stay because I had no other choice in order to feed my family. Someday the Kelvin Gastelum’s and the Yair Rodriguez’s and the Paige VanZant’s will be sitting in their respective emergency rooms with their respective Nick [Palmisciano]’s talking about it being over. And when that day comes, I want to make sure their future is secure.”

For that cause, Kennedy said in his post-fight career it’s full steam ahead.

“I think my involvement directly with mixed martial arts will be specifically in that capacity,” he said. “I’m going to be a martial artist until the day I die. I’m going to be competitive guy. I want to fight to fight Fedor [Emelianenko] in a super-fight grappling competition. I want to rematch Roger [Gracie], but maybe in a gi this time so he has a chance. I’m not done, it’s just the fights that I’m going to be picking will be much more meaningful, much more significant.”

Kennedy, who was at a weapon’s convention on his first day of retirement, reiterated that there’s a big picture component to his overall fight, which helps deal with the finality of walking away.

“MMA on an athlete’s side is a very selfish, lonely thing,” he said. “The things that I’m going to be fighting for are vastly more important than winning the title, or fighting for a fight purse. This is real stuff, that might permanently affect how this sport is shaped.”

Kennedy had a strong run in both the loaded Strikeforce and UFC middleweight divisions, having stood in against a who’s who. He fought Ronaldo Souza and former UFC champion Luke Rockhold, and defeated future champions Robbie Lawler and Michael Bisping.

Asked about what he wants his overall legacy to be, when it’s all said and done beyond just his fighting career, Kennedy downplayed the word itself. He said the idea was to leave things in a better state than where he found them.

“I don’t care about a legacy,” he said. “If someone ever mentions my name again, regarding what I did in the sport as a competitor or now I think as somebody that’s going to reshape how it is now and how it affects athletes, I’m okay with that. Because I’m still going to make change. I am guy that fought for the biggest promotions in the world, in the darkest and dirtiest eras of the sport, against the most roided-out dudes we’ll ever see compete in the sport, and I was one of the best.

“I never ended up being the best, and that’s what I wanted. So, now it’s about the more important things.”

Kennedy did say that the MMA world would continue to hear from him regularly through his work with the MMAAA.

“Yeah, this is not a slow-moving thing,” he said. “This is not a lawsuit that is going to take years. You’re going to see announcements every month. You’re going to see who’s part of this outspokenly, who are athletes on the roster that have already joined. You’re going to see content about why this is important coming out. And if you saw me fight, and you saw how I fought in the cage, this is something that I think is much more important than my performance, and I’ll fight much more fiercely.”