Police responding to a report of a shooting found Cornelius at his Mulholland Drive home around 4 a.m. He was pronounced dead of a self-inflicted gunshot wound about an hour later at Cedars-Sinai Medical Center, according to the coroner's office.
A police cruiser sat parked at the entryway of Cornelius' home on a two-lane stretch of Mulholland Drive in the hills above Los Angeles as detectives searched inside. News cameras camped outside as drivers on their morning commute drove by.
Police Officer Sara Faden said authorities have ruled out foul play. Detectives have not found a suicide note and are talking to relatives about his mental state.
His death prompted many to speak of the positive influence he and his show had on pop culture, music and the black community.
"God bless him for the solid good and wholesome foundation he provided for young adults worldwide and the unity and brotherhood he singlehandedly brought about with his most memorable creation of 'Soul Train,'" said Aretha Franklin, an early performer on the show.
Franklin called Cornelius "an American treasure."
The Rev. Jesse Jackson told KNX-Los Angeles that Cornelius "was a transformer."
"'Soul Train' became the outlet for African-Americans," Jackson said, adding that he talked to Cornelius a few days ago and there were no signs Cornelius was upset.
Others also expressed their grief.
"I am shocked and deeply saddened at the sudden passing of my friend, colleague, and business partner Don Cornelius," Quincy Jones said. "Don was a visionary pioneer and a giant in our business. Before MTV there was 'Soul Train,' that will be the great legacy of Don Cornelius.
"His contributions to television, music and our culture as a whole will never be matched," he said. "My heart goes out to Don's family and loved ones."
Clarence Avant, former chairman of Motown Records, said, "Don Cornelius' legacy to music, especially black music, will be forever cemented in history. 'Soul Train' was the first and only television show to showcase and put a spotlight on black artists at a time when there were few African-Americans on television at all, and that was the great vision of Don."
"Soul Train" began in 1970 in Chicago on WCIU-TV as a local program and aired nationally from 1971 to 2006.
It showcased such legendary artists as Franklin, Marvin Gaye and Barry White and brought the best R&B, soul and later hip-hop acts to TV and had teenagers dance to them. It was one of the first shows to showcase African-Americans prominently, although the dance group was racially mixed. Cornelius was the first host and executive producer.
"There was not programming that targeted any particular ethnicity," he said in 2006, then added: "I'm trying to use euphemisms here, trying to avoid saying there was no television for black folks, which they knew was for them."
Chairman and chief executive of Black Entertainment Television Debra Lee cited Cornelius as a personal role model. She said she used to finish her chores early on Saturday mornings so she could check out the latest music, fashions and dance moves on the show.
"He was such a pioneer in the black music space but also in the black business space," she said. "He created the show in a very hostile environment. He made it a success and he made it a destination for African-Americans and lovers of our culture all over the country and all over the world.
"His reach is just amazing, and personally he was such a charming man," she continued, calling Cornelius "a great interviewer who knew how to connect to artists" and had "the best voice in the world."
Earvin "Magic" Johnson also cited Cornelius' business acumen.
"Don Cornelius was a pioneer & a trailblazer," Johnson wrote on Twitter. "He was the first African-American to create, produce, host & more importantly OWN his own show."
And, Johnson added, "Soul Train taught the world how to dance!"
Other entertainers and music fans also shared their thoughts about the show and its creator on Twitter, where both Cornelius and "Soul Train" were top topics Wednesday.
Singer-actor Ginuwine remembered the smooth-voiced producer as "someone who paved the way for black music."
"I still remember my first time on soul train," he wrote, "what an experience."
On his blog, music mogul Russell Simmons called Cornelius "one of the greatest music legends there was."
"Don Cornelius gave artists who had been segregated from most mainstream vehicles of expression a chance to perform in front of a huge national audience," Simmons wrote. "It was a tremendous opportunity that changed their careers and the whole music industry. To win a Soul Train Music Award meant that the most sophisticated tastemakers in the world loved your work."
"Soul Train," with its trademark opening of an animated chugging train, was not, however, an immediate success for Cornelius, an ex-disc jockey with a baritone rumble and cool manner.
Only a handful of stations initially were receptive.
"When we rolled it out, there were only eight takers," he recalled in a 2006 interview with The Associated Press. "Which was somewhere between a little disappointing and a whole lot disappointing."
The reasons he heard? "There was just, 'We don't want it. We pass,'" he said, with race going unmentioned. "No one was blatant enough to say that."
"Soul Train" had arrived on the scene at a time when the country was still reeling from the civil rights movement, political upheaval and cultural swings. It also arrived when black faces on TV were an event, not a regular occurrence.
"Soul Train" was seen by some at first as the black "American Bandstand," the mainstay TV music show hosted by Dick Clark. While "American Bandstand" featured black artists, it was more of a showcase for white artists and very mainstream black performers.
"Soul Train" followed some of the "Bandstand" format, as it had an audience and young dancers. But that's where the comparisons stopped. Cornelius, the suave, ultra-cool emcee, made "Soul Train" appointment viewing by creating a show that showed another side of black music and culture.
When it started, glistening Afros dominated the set, as young blacks boogied and shimmied to the music of the likes of Earth Wind & Fire and other acts perhaps less likely to get on "American Bandstand."
"May u rest in peace and thank u 4 ur platform," rapper Q-Tip wrote on Twitter. "U will always be remembered."
People tuned into to see the musical acts, but the dancers soon became as much of a main attraction. They introduced Americans to new dances and fashion styles, and made the "Soul Train" dance line - where people stand line up on each side while others sashay down to show their moves - a cultural flashpoint.
"The 'Soul Train' line - that will go down in history as a way of dancing at parties all around the world," Lee said.
Though "Soul Train" became the longest-running syndicated show in TV history, its power began to wane in the 1980s and '90s as American pop culture began folding in black culture instead of keeping it segregated. By that time, there were more options for black artists to appear on mainstream shows, and on shows like "American Bandstand," blacks could be seen dancing along with whites.
But even when Michael Jackson became the King of Pop, there was still a need to highlight the achievements of African-Americans that were still marginalized at mainstream events. So Cornelius created the "Soul Train Awards," which would become a key honor for musicians. The series also spawned the Soul Train Lady of Soul Awards and the Soul Train Christmas Starfest.
Cornelius, who was inducted into the Broadcasting and Cable Hall of Fame in 1995 and has a star on the Hollywood Walk of Fame, said in 2006 he remained grateful to the musicians who made "Soul Train" the destination for the best and latest in black music.
"I figured as long as the music stayed hot and important and good, that there would always be a reason for 'Soul Train,'" Cornelius said.
Neil Portnow, president and chief executive of the Recording Academy, called "Soul Train" a cultural phenomenon and its creator "a true visionary and trailblazer."
"He made an indelible impact on American television, one that will continue to be appreciated for generations to come," Portnow said. "His beautiful, deep voice and measured pace always sounded warm and familiar to the millions who admired and followed his broadcasts."
Cornelius stepped down as "Soul Train" host in 1993. The awards returned to the air in 2009 after two-year hiatus. Last year's awards were held on Nov. 27 in Atlanta, with Earth Wind & Fire receiving the "Legend Award."
In his later years, Cornelius had a troubled marriage. In 2009, he was sentenced to three years' probation after pleading no contest to misdemeanor spousal battery. In his divorce case that year, he also mentioned having significant health issues.