"I've had an incredibly special time playing for the L.A. Galaxy," Beckham said in a statement. "However, I wanted to experience one last challenge before the end of my playing career. I don't see this as the end of my relationship with the league, as my ambition is to be part of the ownership structure in the future."
Beckham has played in Los Angeles for six seasons since his groundbreaking move from Real Madrid, reaching three league finals and winning one MLS title last year during his best stateside campaign.
He agreed to a two-year contract extension with the Galaxy in January after playing out his initial five-year deal, turning down potential moves to wealthy Paris Saint-Germain and other clubs including at least one Premiership team, according to Beckham.
Beckham hadn't given any overt indications he was planning to leave the Galaxy after this season with a year left on his deal. Last week, the longtime England captain pointedly denied rumors linking him to a short-term stint in Australia.
Beckham has been the star player for MLS' highest-profile franchise during his tenure, which began with a handful of rocky seasons before the Galaxy became a power under coach Bruce Arena in recent years. As Beckham indicated in his news release, his MLS contract includes the option to purchase a league franchise when his playing career ends, and Beckham has long been keen on an ownership move.
"In my time here I have seen the popularity of the game grow every year," Beckham said. "I've been fortunate to win trophies, but more important to me has been the fantastic reception I've had from fans in L.A. and across the States. Soccer's potential has no limits in this wonderful country, and I want to always be part of growing it."
Beckham's announcement indicated the MLS Cup will be his final "competitive" match with the Galaxy, which means he might participate in lucrative overseas friendlies often played by the Galaxy in recent years. But Los Angeles has no overseas exhibitions currently scheduled, so the championship game might be his final bow.
"Seldom does an athlete redefine a sport," said Tim Leiweke, the president of Galaxy owners AEG. "David not only took our franchise to another level, but he took our sport to another level It has been an honor and privilege to be a part of his world, and more importantly, to have him be a part of ours."
Beckham has been among MLS' top players when healthy throughout his contract, and the gifted playmaker has meshed well with fellow international stars Robbie Keane and Landon Donovan during the Galaxy's past two seasons. Los Angeles got off to a slow start this year, but has played splendidly down the stretch and into the postseason, rolling to a first-round elimination of the Supporters' Shield-winning San Jose Earthquakes and a two-game victory over the Seattle Sounders in the Western Conference finals.
MLS has grown exponentially during Beckham's tenure as the league's face, expanding to 19 North American teams with record attendance and much-improved broadcast deals. The Galaxy reached the most lucrative television deal in MLS history last year with Time Warner Cable Sports.
"There is no doubt that MLS is far more popular and important here and abroad than it was when he arrived," MLS Commissioner Don Garber said. "David has achieved great things on and off the field during his time with the Galaxy, and he will always be an important part of our history. We look forward to his continued involvement with the L.A. Galaxy and the league."
Beckham began his pro career with 12 years at Manchester United before his move to Real Madrid. He left for the Galaxy in 2007, building on a worldwide fame that reportedly produces more than $40 million per year in endorsement income.
Beckham played in three World Cups and made a record 115 appearances for England, but wasn't chosen for the Olympic team at the London Games last summer. Beckham still played a role in the Olympic festivities, including a prominent part in the lighting of the Olympic flame in his native east London during the opening ceremonies.
Beckham and his wife, former Spice Girl Victoria, seem comfortable in Los Angeles, where their three sons Brooklyn, Romeo and Cruz attend school. Beckham is a fixture in the Los Angeles Lakers' courtside seats, attending his most recent game with his three sons last Friday.