The 33-year-old South Korea international signed an initial two-year deal, admitting that LAFC was not his initial preferred destination but he was persuaded by the club's general manager.
He expressed that leaving Spurs was the “hardest decision ever” and left him feeling “very empty”, but he sought a new chapter and challenge.
The move sees Son reunite with former Spurs teammate Hugo Lloris in Los Angeles, a city with a significant Korean population, ahead of next summer's World Cup in the United States.