Lincoln City, who play in the third-tier League One, said Donovan's role will be to work with the front office to enhance the club's profile in North America. The Imps also said that Arizona-based businessman Harvey Jabara will become a minority owner in the team.
"At the end of last year, through a mutual friend, who is also an intermediary, I just started following the club as I passed it on to Harvey to look at," Donovan told Lincolnshire Live. "My role is that at any point, in any way, if they need help with anything, then I'm happy to try to help.
"But you don't come into a club that's been this successful and pretend like you're going to have much to add.
"I'm more of a fan while I'm happy to help in a small way to get this over the line."
Donovan, 39, has 157 international caps and is the joint all-time goal scorer with fellow USMNT legend Clint Dempsey at 57. Donovan won the MLS Cup six times in his playing career, twice with the San Jose Earthquakes and four times with the LA Galaxy, as well as playing in the Bundesliga for Bayer Leverkusen and the Premier League for Everton.
Since 2019, Donovan has been coach and vice president of soccer operations for United Soccer League side San Diego Loyal. He is also part of the ownership group that owns Championship Swansea City.
"We are continually on the lookout for like-minded people to join our current group of investors to assist with the ongoing development of the club financially, and also importantly, contribute their knowledge and acumen," Lincoln chairman Clive Nates said.
"We have been talking to Harvey and Landon for some time now, but right from the initial meetings, it was clear to see we were aligned in our vision and values for the club.
"It is great for all that we can also benefit from Landon and his vast experience."
Lincoln City reached League One after winning the fourth-division League Two title after the 2018-19 season. They also won the Football League Trophy in 2018.