The Atlanta Braves' closer unanimously won the award Monday, with Tampa Bay pitcher Jeremy Hellickson emerging from a talented crop to take the AL honor.
"It definitely did surprise me," Kimbrel said on a conference call from his vacation in Hawaii. "I expected it to be close."
The AL Cy Young Award will be announced Tuesday. Detroit ace Justin Verlander is expected to easily win.
"He's the best pitcher in the game," Hellickson said.
Kimbrel set a major league record for saves by a rookie with 46. He earned all 32 first-place votes in balloting by the Baseball Writers' Association of America and outpointed Braves teammate Freddie Freeman.
The hard-throwing righty was dominant for much of the year and chosen as an NL All-Star during his streak of 38 straight appearances without allowing a run. But that string ended in mid-September and the 23-year-old Kimbrel was wobbly as the Braves frittered away a 10 1/2-game lead in the NL wild-card race.
Kimbrel's eighth blown save of the year came in the final game of the season, when he walked three, gave up a hit and allowed the tying run in the ninth inning against Philadelphia. The Phillies went on to win in the 13th, costing the Braves a spot in a one-game playoff against St. Louis for the wild-card slot.
"I blew many saves throughout the year. It just so happened that one came in the last game of the year with everything on the line," he said. "My control was not there, I was all over the place.
"I'm going to get over it, but I'm not going to forget it," he said. "I need to fix it."
Kimbrel struck out 127 in only 77 innings and anchored Atlanta's outstanding bullpen, pitching 79 games. He was 4-3 with a 2.10 ERA, and his long scoreless span covered 37 2-3 innings.
"I did learn that the season is long," he said.
Kimbrel wound up tied for Milwaukee's John Axford for the NL lead in saves. He became the 10th unanimous NL rookie winner, and first since Albert Pujols in 2001. Kimbrel was the seventh Braves player to win the award that began in 1947, and first since Rafael Furcal in 2000.
"There's a lot of room for improvement," Kimbrel said.
Kimbrel, who pitched 21 games in 2010 but still retained his rookie eligibility by throwing under 50 innings, earned 160 points in the BBWAA balloting. Freeman, who hit .282 with 21 home runs and 76 RBIs, was second with 21 second-place votes and 70 points. Kimbrel and Freeman became the first pair of teammates to finish 1-2 in the NL rookie voting since Cubs outfielders Jerome Walton and Dwight Smith in 1989.
Philadelphia pitcher Vance Worley was third and Washington catcher Wilson Ramos was fourth. Ramos was kidnapped in Venezuela last week and freed Saturday when commandos raided the mountain hideout where he was being held.
Hellickson went 13-10 with a 2.95 ERA in helping the Rays take the AL wild-card spot. He drew 17 of 28 first-place votes and finished well ahead of Los Angeles Angels first baseman Mark Trumbo.
"It's something I really wanted to win," Hellickson said on a conference call from his home in Iowa. He said there were "three or four guys" equally deserving of the award.
The 24-year-old Hellickson was a big reason the Rays were able to erase a nine-game deficit against Boston in the last 3 1/2 weeks to win the AL wild-card spot. He was unbeaten in five starts against AL East teams in the final month, and finished 7-3 in games against division rivals.
On the next-to-last day, he kept the Rays close against the visiting New York Yankees. On his final pitch of the regular season, Hellickson got Russell Martin to ground into a triple play with the bases loaded, and the Rays went on to win.
Hellickson, incidentally, has a Yorkshire terrier called Jeter — as in, Yankees star Derek Jeter. Hellickson's dad was a big Reggie Jackson fan, and the dog wound up with the name.
Hellickson is generously listed at 6-foot-1, but held up extremely well over 29 starts. He led all big league rookies in ERA, innings (189) and opponents' batting average (.210).
He became only the second AL starting pitcher to win the award in 30 years, along with Verlander in 2006. Hellickson's ERA was the best for qualifying AL rookies since Kevin Appier's 2.76 in 1990.
"I've believed in myself and had all the confidence in the world in myself," he said.
Like Kimbrel, Hellickson's final outing was rocky. Against Texas in Game 4 in the opening round of the AL playoffs, he gave up a leadoff home run to Ian Kinsler and two homers to Adrian Beltre and left after four innings as the Rangers clinched the series.
Hellickson, who went 4-0 in 10 for the Rays in 2010, joined Evan Longoria (2008) as Tampa Bay players to win the AL rookie honor. Hellickson finished with 102 points.
Trumbo drew five first-place votes and 63 points. Eric Hosmer, who hit .293 with 19 home runs and 78 RBIs after being called up by Kansas City in May, got four first-place votes and 38 points. Ivan Nova, 16-4 with a 3.70 ERA for the Yankees, got one first-place vote and was fourth with 30. Seattle second baseman Dustin Ackley drew the other first-place vote.