With the win Bradley now moves into sixth in the Fedex Cup standings while also capturing his first Tour Championship birth since 2014.
"A lot has happened to me over these six years", he said.
"It's been a consistent season so I'm glad to have made the Tour Champs - hopefully my last event of the year will be my best and I can get a win", Leishman, whose 68 lifted him to a share of 41st at six under.
Bradley, 32, burst onto the scene with a major victory at the 2011 PGA Championship, but until Monday had not won since 2012.
Rose lost a playoff against American Keegan Bradley in suburban Philadelphia. As well as Bradley had been playing (66-64-66 through three rounds), he was three shots behind Rose, and losing time quickly. Bradley played first and chipped to within two feet. The even-par round of 70 on Friday after opening the tournament with 62 was the real difference. His chances to represent USA teams in worldwide play had dried up, his preferred putting method was banned, and the confidence that once put him on the cusp of greatness was shot.
Keegan Bradley might be there, too, all because of one putt. "You look at the scores, 20 under par". A birdie at the 16th hole, making up for a bogey on No. 14, inspired a roar from the crowd.
Rory McIlroy and Tiger Woods both confirmed their spots in the season-ending Tour Championship, but who will not be teeing it up in Atlanta?
Nawaz Sharif's wife Kulsoom Nawaz dies in London
Former three-time Pakistan prime minister Nawaz Sharif's wife, Kulsoom Nawaz, breathed her last at a London hospital on Tuesday. This was reportedly the last time Nawaz Sharif had spoken to his wife. "In a personal capacity, she was a very loving woman".
The Co Down man gave himself 13 birdie putts in his first 13 holes, including seven inside 15 feet. For the week, he was a modest 31st in the 69-player field in strokes gained, putting.
His final round was steady in the extreme, nine greens in regulation on the front nine, nine pars. He had 27 putts on Monday. "But at the end of the season here, to say that I've made it back to the Tour Championship after what I've been through is a pretty good accomplishment".
Bradley and Xander Schauffele, who finished one shot out of the playoff, moved into the top 30 to qualify for East Lake, and Emiliano Grillo joined Spieth as the two players who fell out.
All of it was procedural, as Woods was sure to get a special exemption from the United States Golf Association. He gets a trip to Maui to start next year for the winners-only Sentry Tournament of Champions.
Perhaps most important of all to Woods - the Tour Championship offers another chance for a victory, where he will need to defeat just 29 players.