Police reportedly discovered Cornelius with a gunshot wound to his head early Wednesday (February 1) morning, according to TMZ.
Law enforcement sources have said that they believe the bullet wound was self-inflicted.
Cornelius was rushed to a Los Angeles hospital, but was pronounced dead upon arrival.
The music legend's family have been notified of his passing, according to police.
Cornelius earned his reputation as a music industry icon when he launched Soul Train in 1971.
Soul Train was one of the first US television programmes to cater to African-American audiences by featuring cutting-edge funk, jazz, disco, R&B and gospel performers.
Michael Jackson, Aretha Franklin, and 'The Godfather of Soul' James Brown were among the many iconic musicians to grace the Soul Train stage over its 35-year run.
The deep-voiced Cornelius served as the regular host of Soul Train from 1971 to 1993, before handing over presenting duties to Mystro Clark, Shemar Moore and Dorian Gregory.
Soul Train aired its last original episode in 2006, but series continues to be broadcast in syndication.
Rapper Ice Cube is among the stars paying tribute to the late Cornelius, tweeting on Tuesday morning: "Rest in Peace, Love & Soul...Don Cornelius."
Recording Academy president Neil Portnow said: "Don Cornelius made an indelible impact on American television, one that will continue to be appreciated for generations to come.
"The music industry has lost a true visionary and trailblazer, and our deepest sympathies extend to his family, friends, and all who welcomed him in their homes for so many years."
'Super Bass' singer Nicki Minaj also expressed her condolences on Twitter by writing: "R.I.P. Mr. Cornelius."
Cornelius was 75 years old.
> Soul Train to get big screen treatment
Watch Don Cornelius interview James Brown on a 1974 episode of Soul Train below: