The 37-year-old has teamed up with the Walton-Penner Family Ownership Group, which took over the Broncos in a reported $4.65billion - around £3.81billion - swoop in June.
A statement from Rob Walton, heir to the Walmart fortune, said: "We're delighted to welcome seven-time Formula One world champion Sir Lewis Hamilton to our ownership group.
"He is a champion competitor who knows what it takes to lead a winning team and a fierce advocate for global equality, including in his own sport.
"With over 100 race wins, Lewis is considered the most successful F1 driver of all time. His resilient spirit and standard of excellence will be an asset to the ownership group and the Broncos organization."
Hamilton had tried to expand his investment portfolio in May when getting involved in one of the Chelsea takeover bids, but was unsuccessful.
The ownership group led by Walton includes his daughter, Carrie Walton Penner, and her husband, Greg Penner.
It was boosted last month by the addition of former US Secretary of State Condoleezza Rice, who served under President George W. Bush from 2005 until 2009.
Stevenage-born Hamilton, 37, made his name in kart racing before working his way through the ranks to Formula 1 for his debut season in 2007.
He won his first world title just a year later and collected his record-equalling seventh in 2020, only being denied an eighth in dramatic and controversial fashion by Max Verstappen on the final day of last season.
The Denver Broncos are three-time Super Bowl winners with their last success coming in 2015.