In 2005, after six years with Leverkusen, the majority of which were spent on loan with the San Jose Earthquakes of MLS, Donovan moved back to the United States permanently to sign with the Los Angeles Galaxy.

[18] In 1999 Donovan attended the IMG Academy in Bradenton, Florida, with other members of the U-17 national team as part of U.S. Soccer's youth development program.

He was named Player of the Tournament for his role in the United States under-17 squad that finished fourth in the 1999 FIFA U-17 World Championship before signing with German club Bayer Leverkusen later that year.

Later in 1999, Donovan signed a six-year contract for German Bundesliga club Bayer Leverkusen, whose sporting director Michael Reschke spotted him at a youth tournament in Europe.

Upon his re-entry to MLS, San Jose was denied the chance to re-sign Donovan because Earthquakes general manager Alexi Lalas had traded away his rights.

LA Galaxy, his hometown team, were able to trade leading scorer Carlos Ruiz to FC Dallas to get on top of the MLS allocation order as Donovan prepared to leave Germany.

Although the 2008 season was a disappointment for LA Galaxy, it was a banner year for Donovan as he scored 20 goals and nine assists in 25 matches, forming a strong offensive partnership with David Beckham and Edson Buddle.

[31] After his former national team manager Bruce Arena was named LA Galaxy head coach and Beckham joined Milan on loan in early 2009, Donovan once again was given the club captaincy on a permanent basis.

Following the season, Donovan agreed to a four-year extension to his contract with LA Galaxy, with clauses that allow him to seek loans during the MLS offseason.

In October 2012, Donovan expressed his desire to take a break from his professional soccer career, citing physical and mental exhaustion as the main reasons.

[37] On August 6, 2014, he scored the winning goal at the 2014 MLS All-Star Game, putting the ball past Bayern Munich goalkeeper Manuel Neuer at the 70th minute, he was subsequently substituted for Sporting Kansas City striker Dom Dwyer and gave the captain's armband to Canadian international Will Johnson.

[45] Everton were keen on extending his loan deal, but LA Galaxy refused,[46] and Donovan returned to the U.S. in time for the start of the 2010 MLS season.

I spoke with some of them that week and they jokingly asked if I was ready to make a return to the field to help fill some of the void left by the injuries and departures.

[60] He provided an assist in a 6–4 win over the Tacoma Stars during his MASL debut on February 15 in front of a record crowd in Pechanga Arena San Diego.

[65] Donovan was a member of the inaugural class at U.S. Soccer's full-time residency program for the under-17 national team at the IMG Academy in Bradenton, Florida.

On October 10, 2009, Donovan scored on a free-kick, giving the U.S. a 3–2 victory over Honduras in San Pedro Sula that clinched World Cup qualification.

Donovan was recalled to the full national squad for the first time in over a year for the U.S.'s September World Cup qualifying matches against Costa Rica and Mexico.

With the U.S. needing a win over Mexico to clinch qualification, Donovan's corner kick assisted Eddie Johnson's go-ahead goal in the 57th minute.

[86] Donovan was a versatile attacker known for his pace and stamina as well as intelligence and technical skill,[87] allowing him to play at various forward and midfield positions at different points of his career.

As his professional career progressed, Donovan was increasingly utilized by managers as a wide attacking midfielder, where he could additionally benefit the team with his playmaking abilities, passing vision, and defensive work rate.

[88][89] Donovan also provided capable delivery on set pieces (as well as occasionally scoring from direct kicks) and served as first-choice penalty taker for club and country for much of his career.

Donovan led a team of MLS academy graduates, assembled just one day prior, to a 1–1 regulation tie, followed by a 4–5 shootout loss, as reported online.

On November 14, 2019, Landon Donovan was named the inaugural manager of the San Diego Loyal, a team that he helped co-found and was the vice president of soccer operations.

He brought on former coach Paul Buckle and former United States women's national soccer team player Shannon MacMillan as senior advisors to his staff.

[96] Donovan and the Loyal garnered international headlines when they forfeited the last two matches of the season after having alleged instances of racial and homophobic abuse directed at their players by the Los Angeles Galaxy II and Phoenix Rising respectively went unpunished.

[102] After his retirement, Donovan became a color commentator for FOX Sports, participating in the network's coverage of the United States–Ecuador quarter-final of the Copa América Centenario.

[103] He also called the USMNT games on Fox with John Strong and Stuart Holden[104][105] and then teamed up with ESPN/ABC's lead play-by-play announcer Ian Darke for the 2022 World Cup and Euro 2024.

[109] On 17 June 2021, it was announced that Donovan would be joining Lincoln City as a Strategic Advisor, working with the Board, Chief Executive Liam Scully and Director of Football Jez George to enhance the club's network and relationships, particularly within North America.

[114] Donovan has spoken publicly about dealing with depression throughout his life and career, and has criticized the professional sports world for its approach to mental health issues.

[123] Donovan revealed during the 2018 FIFA World Cup that he was a fan of fierce rival Mexico in the absence of the United States national team, having been sponsored to do so by Wells Fargo.