Ryan Braun participant of 2008 Major League Baseball season
2008: All-Star and Silver Slugger
In March 2008, the Brewers renewed Braun's contract for $455,000, a $75,000 increase. Braun then signed an 8-year, $45–$51 million contract extension (the total depending on his "Super 2" service-time ranking after the 2009 season) on May 15, 2008.  The contract was through the year 2015. The deal included Braun's $455,000 salary for 2008, and a $2.3 million bonus in 2008. It could have increased to $51 million through incentives. Braun also had a no-trade clause for the first four years, and then a limited no-trade clause allowing him to block deals to 12 teams from 2012 to 2013, and 6 teams from 2014 to 2015. The contract would keep Braun locked up through his age-31 season. It was the largest contract in Brewers' history, surpassing Jeff Suppan's. It was also the largest contract in baseball history given to a player with less than three years' experience.  Braun's agent, Nez Balelo, crunched enough numbers to show him what he potentially could have made over the life of this contract if he had chosen not to sign it. "But the question I ultimately asked myself was, `What can't I buy with that amount of money?"' Braun said.Braun drove in 134 runs in his first 162 games in the majors, more RBIs than any active player.  He reached the 150-RBI milestone faster than any major leaguer since Boston's Walt Dropo needed only 155 games, in 1949–51.  On June 17, 2008, he drove in his 152nd career RBI, in his 182nd game.Braun was named the NL's Player of the Month, after batting .366 in July (6th in the NL) with 9 home runs (3rd), and 23 RBIs (7th). He also led the league with 76 total bases and 18 extra base hits, and was among NL leaders with 37 hits (2nd), 3 triples (2nd), and a 1.163 OPS (3rd). He had back-to-back 4-hit games, just the 5th player in team history to accomplish that feat. "It's a huge honor", Braun said. "The way I look at it, you're the MVP of the National League for that month. It's definitely a big accomplishment.As of August 8, Braun's major league career start was one of the best ever.  In 227 games to start a career, he was first with 558 total bases and 133 extra base hits, second with 64 home runs, and tied for second with 181 RBIs.On August 9, Braun strained the intercostal muscles around his oblique ribcage.  That led to him missing a number of games, and shortening his swing for a few weeks.  After returning, on September 25 he hit his first grand slam, delivering a 2-out, 2–2 pitch from the Pirates' Jesse Chavez into the left field bleachers of Miller Park in the bottom of the 10th inning, winning the game 5–1, and keeping the Brewers' 2008 postseason hopes alive. Braun became the first—and as of July 2018, the only—player to hit a walk-off grand slam at Miller Park. Three days later, Braun helped put the Brewers into the postseason for the first time since 1982, by hitting a go-ahead 2-run homer in the bottom of the 8th against the Chicago Cubs. The homer was the difference in the game, which gave the Brewers a one-game lead over the New York Mets for the NL wild card.
Braun was a starting outfielder for the NL in the 2008 All Star Game. He finished first in fan voting among NL outfielders, and second among all NL players, with 3,835,840 votes, behind only Chase Utley of the Phillies (3,889,602). He also finished first in player voting. Braun was the first Brewers outfielder voted to start an All Star game. He was one of seven first-time starters in the game, and–along with Kosuke Fukudome and Josh Hamilton–one of only three who had not reached the major leagues until 2007 or 2008.Braun came in third in the Home Run Derby at Yankee Stadium. "It's something you dream about", Braun said. "That's as big a stage as you can get on.... it's going to be a lot of fun." He had his friend and agent, Nez Balelo, a former minor league infielder, pitch to him. He hit seven home runs in each of the first and second rounds, finishing with 14 (three behind finalist Justin Morneau, who hit five in the final round to win the Derby).On June 3, Braun became the third-fastest major leaguer to reach 50 career home runs.  He did so in 171 career games; the only players to reach that plateau sooner were Rudy York and Mark McGwire.  On July 8, Braun hit his 56th home run in his 200th game, the third-highest total ever in a major leaguer's initial 200 games, behind McGwire (59) and York (59).In early August, Braun hit his 30th home run, becoming just the second player in MLB history to hit 30 or more homers in each of his first two seasons.  Braun hit 71 home runs in his first two seasons, tying him with Pujols for fourth all-time. Joe DiMaggio tops the list with 75 home runs, followed by Ralph Kiner (74) and Eddie Mathews (72).In 2008, in 151 games Braun hit 37 home runs (tied for 4th in the NL, behind Ryan Howard, Adam Dunn, and Carlos Delgado), with 106 RBIs (9th), and batted .285 with a .553 slugging percentage (5th).  He also led the league with 83 extra base hits, and had 338 total bases (2nd in the NL), 7 triples (6th), 16.5 at-bats-per-home-run (10th), and 611 at bats (10th).  12.5% of his plate appearances were extra base hits (3rd in the NL; behind Ryan Ludwick and Pujols), he had 29 infield hits (7th), and he stole third base 6 times (9th).Against starting pitchers, Braun hit .244 the first time he faced them in a game, .331 the second time, and .328 with a .672 slugging percentage the third time.  Braun led the Brewers in batting average, slugging percentage, triples, home runs, RBIs, extra base hits, total bases, at-bats-per-home run, OPS (.888), runs (92), and hits (174).Braun hit .313 in October against the Phillies in his first postseason series, which the Brewers lost 3–1.
Braun was voted to the 2008 NL Sporting News All Star Team, by a panel of 41 major league general managers and assistant general managers. He also won the 2008 NL Outfielder Silver Slugger Award. In voting for the 2008 NL MVP award, Braun was third (with 139 points), behind Pujols and Ryan Howard.