According to Front Office Sports, Harden has acquired a five per cent stake in the club that values the franchise at more than US$475 million.
Harden, who in 2017 signed a then-NBA record US$228 million dollar contract extension with the Houston Rockets through to the 2022/23 season, becomes the fifth member of the ownership group, which also owns the National Women's Soccer League's (NWSL) Houston Dash and the BBVA Stadium.
The group is led by Mexican businessman Gabriel Brener,
The other members of the group are Ben Guill, Jake Silverstein and former boxing world champion Oscar De La Hoya, all of whom are expected to continue their involvement after the basketball player's investment.
Harden said: "Houston is my home now, and I saw this as a way to invest in my city and expand my business interests at the same time. Soccer in general, and especially MLS, have exploded in this country throughout my lifetime. I've been a fan of the game for several years, and I know that Houston has a massive soccer fanbase, so it was an easy decision for me when this opportunity arose."
Brener added: "We are thrilled to welcome James into our club. He's an icon in the Houston community, and not only is he a great basketball player, he has an extremely smart and savvy mind for business.
"James will bring a very unique perspective to our ownership group, and I'm looking forward to hearing his thoughts and opinions on the club going forward."