Boseman died of cancer in August. He was 43.
In addition to starring in Black Panther and other superhero blockbusters in the Marvel Cinematic Universe, Boseman acted in the films Da 5 Bloods, 42, Marshall and Get On Up. He will soon be seen in Ma Rainey's Black Bottom.
Boseman was named Hero for the Ages on Sunday's MTV program.
"Mr. Boseman truly embodied what it meant to be a superhero," Downey said. "And he wasn't just a hero onscreen. His list of selfless and inspirational acts and deeds is too long to recount here, consistently showing up during trial and triumph for family, friends, and fans alike, some of whom were battling the same invisible enemy. He was the most heroic when just being Chad."
"Each time he stepped on the set, he inspired and influenced there," Cheadle added. "He had an incredible power to unify people in their love for his work and their respect for him as a person. The way he lived his life united people behind a higher purpose, and that will be his legacy."
Kevin Hart scored the award for Comedy Giant during the ceremony, while Wonder Woman 1984 star Gal Gadot earned the She-ro accolade and The Wedding Singer and Fifty First Dates co-stars Drew Barrymore and Adam Sandler won the prize for Dynamic Duo.
Another highlight of the show was when Sarah Michelle Gellar and Selma Blair attempted to recreate their iconic kiss from their 1999 movie, Cruel Intentions, but were separated by a plastic screen due to the coronavirus pandemic.
Actress and singer Vanessa Hudgens hosted the MTV Awards: Greatest of All Time.