"The fans here have always been very supportive of me, and I appreciate that," said the 45-year-old Johnson, a five-time Cy Young Award winner whose contract expires after this season. "In some small way, hopefully, I've been able to give something back on the field and off the field."
The Diamondbacks won it in the ninth when Luis Vizcaino (1-2) issued a bases-loaded walk to Chris Young, who had tied the game with a solo homer in the eighth off Manuel Corpas.
"I guess you really couldn't ask for anything more, the way the game ended today," Johnson said. "It was pretty exciting. A little too much excitement, to be honest with you."
Fueled by several standing ovations from the Chase Field crowd of 35,908, Johnson (11-10) returned to his once-dominant form, allowing only an unearned run and two singles to Troy Tulowitzki. He walked one and struck out nine in his second complete game this season and the 100th of his career, more than any active pitcher besides Greg Maddux, with 109.
This game meant nothing in the standings, where the defending NL West champions finished 82-80, two games behind Los Angeles. But manager Bob Melvin said he knew Johnson was motivated when the pitcher approached him last week.
"A couple of days ago, he walked by me and he said, 'You can throw the pitch count on Sunday out,' " Melvin said. "So I knew right then and there it was a little more than just another game for him."
Now the question is whether Johnson, who lives in nearby Paradise Valley, will be back next season - with Arizona or another club.
"I don't even know what we're having for dinner tonight, so I surely couldn't answer something like that," said Johnson, who has rebounded from multiple back surgeries.
Melvin said he believes Johnson will return.
"That's how I look at it right now," Melvin said. "He still has some things he wants to accomplish and he loves the competition."
Johnson trimmed his ERA by .20 points, finishing at 3.91. The only run Johnson gave up came in an ugly first inning.
Clint Barmes led off with a grounder to third baseman Mark Reynolds, who threw the ball over first baseman Chad Tracy's head for his 35th error.
Barmes reached second on the error and moved up on Tulowitzki's sacrifice bunt. One out later, he scored on a wild pitch - Johnson's second in 176 innings this season.
For seven innings, it looked as if that run might be enough for the Rockies. But unlike last year, when Colorado found ways to win games down the stretch, the Rockies seemed to invent ways to lose this year.
The 2007 NL champs never mounted a serious defense of their pennant. They finished 74-88, 10 games behind the Dodgers.
"Everyone is disappointed, but they aren't going away angry, and it's not like everyone has pom-poms, happy the season's over either," manager Clint Hurdle said. "This is just a good team that had a bad season and that is my responsibility."
The Diamondbacks didn't do much against Colorado starter Ubaldo Jimenez, who gave up three hits in seven innings, walking four and striking out 10.
It was the latest in a string of fine starts by Jimenez, who allowed three earned runs or fewer in seven of his last eight outings.
"It's been a learning curve," Jimenez said. "It's been a lot of up and down. I learned a lot of things from that.
"I finished strong, and that's what matters," Jimenez said.
Jimenez' shot at his 13th victory disappeared when Corpas gave up a homer to Young, the second batter he faced in the eighth, tying the game at 1.
Johnson had thrown 101 pitches to that point, but he went back out for the ninth inning, drawing another in a succession of ovations.
The last one came as Johnson walked off after a 1-2-3 ninth. He tipped his cap and, moments later, climbed to the top step of the dugout to acknowledge a curtain call.
Johnson has rarely revealed a sentimental side. But he was clearly touched as he talked about the fans' reception.
"It was pretty heartwarming," Johnson said. "You've got to do a lot of things for a pitcher to get a curtain call. So that meant a lot to me."
Notes: Reynolds struck out twice to extend his major league record to 204 for the season. ... The Diamondbacks were eliminated from playoff contention on Thursday. Word apparently didn't reach the marketing department. An illuminated sign on the loge said, "Buy 2009 season tickets now and guarantee 2008 postseason rights."