Rodney made his Major League debut 2002 at the age of 25 and split his time between the Triple-AToledo Mud Hens and the Tigers from 2002–2005.
In 2005, Rodney became the Tigers closer after Troy Percival went down with an arm injury and his replacement, Kyle Farnsworth, was traded at mid-season to the Atlanta Braves. He was called up from Toledo after Farnsworth was traded, then settled into the closer role, earning nine saves in 39 total appearances, during which he racked up a 2.86 earned run average.
When the Tigers signed closer Todd Jones during the 2006 off-season, Rodney was reinserted into a middle relief/setup role. Rodney embraced the role as the Tigers proceeded to have their most successful season in recent history.
Rodney started 2008 on the disabled list with shoulder tendinitis. He re-joined the big league club in mid-June. On July 27, Rodney was announced as the Tigers' new closer, replacing Todd Jones.
Following the 2009 season, the Tigers offered arbitration to Rodney, which he rejected to pursue a multi-year deal. He was expected to be one of the more valuable closers on the market because as a "Type B" free agent, he would only cost teams a supplementary draft pick. His 1.40 ground ball-to-fly ball ratio ranked first that year among free-agent closers. Originally, the Baltimore Orioles and Philadelphia Phillies were rumored to be interested in signing Rodney. The Los Angeles Angels of Anaheim were also reported to be in serious discussions with his agent.
On December 24, 2009, Rodney signed a two-year, $11 million contract with the Los Angeles Angels of Anaheim. Although he closed for the Detroit Tigers in 2009, "Rodney is expected to share setup duties with Scot Shields and Kevin Jepsen and close on a fill-in basis when Brian Fuentes is down," the LA Times reported.
Rodney states, "I think I'm a different pitcher in save situations," referring to his lower ERA in save situations. He filled in April for Angels' closer Brian Fuentes when he went on the disabled list with a strained back.
Three days after the Los Angeles Angels of Anaheim traded Brian Fuentes on August 27, 2010 to the Minnesota Twins, it was officially announced that Rodney would be the new closer by manager Mike Scioscia. On April 5, 2011, Rodney was replaced by Jordan Walden as the full-time closer.
In late September 2011, Rodney became frustrated after a lack of relief appearances and asked Angels general manager Tony Reagins for a trade.
Rodney signed a $1.75 million deal with the Tampa Bay Rays for the 2012 season. While Kyle Farnsworth was on the 60-day disabled list, Rodney performed in the closer role and has maintained that role since Farnsworth has returned from his injury. He was selected on July 6 to participate in his first ever All-Star Game. On that date, he had converted 24 of 25 save opportunities. At the end of the 2012 season, Rodney had converted 48 saves, the second most that season behind Jim Johnson of the Baltimore Orioles. His 0.60 earned run average for the season was the lowest by a qualifying relief pitcher in major league history. On October 19, 2012, Rodney was named the AL Comeback Player of the Year and the Delivery Man of the Year During his time with the Rays, Rodney appeared to shoot an arrow to high center field after converting a save as his celebration taunt. He is also known for wearing his cap tilted.