Aariel Maynor pleaded guilty in the fatal shooting of Avant and the attempted murder of her security guard at her Beverly Hills home in December, Los Angeles County prosecutors said.
Maynor also pleaded guilty to possession of a firearm by a felon and two counts of burglary.
He is scheduled to be sentenced on March 30 and could be sentenced to up to 170 years in prison, prosecutors said.
“This crime continues to shock the conscience," District Attorney George Gascón said in a statement. “Mrs. Avant’s death was a tragic loss felt by our entire community.”
Gascón said Maynor will be ineligible for elderly parole.
Police were called to the Avants’ home early on the morning of Dec. 1 and found Jacqueline Avant, 81, with a gunshot wound. She was taken to the hospital but did not survive.
He also fired on a security guard, authorities said. Neither the guard nor Clarence Avant was hurt.
An hour later, Los Angeles police officers arrested Maynor, a parolee who had shot himself in the foot at a home in the Hollywood Hills about 7 miles (11.27 kilometers) away. He was arrested for burglary, and hours later was tied to the Avant shooting.
Authorities have said he was burglarizing both homes, and they don't believe he was targeting the Avants.
Jacqueline Avant was a longtime local philanthropist who led organizations that helped low-income neighborhoods including Watts and South Los Angeles, and was on the board of directors of the International Student Center at the University of California, Los Angeles.
Grammy-winning executive Clarence Avant is known as the “Godfather of Black Music” and was inducted into the Rock & Roll Hall of Fame last year. The 91-year-old was also a concert promoter and manager who mentored and helped the careers of artists including Bill Withers, Little Willie John, L.A. Reid, Babyface, Jimmy Jam and Terry Lewis.
The Avants were married for 54 years and had two children, Alexander Du Bois Avant and Nicole Avant, a film producer and former U.S. ambassador to the Bahamas who is married to Netflix co-CEO and Chief Content Officer Ted Sarandos.
Jacqueline Avant's charitable work and personal connections made her a widely beloved figure. After her death, tributes to her came from former President Bill Clinton, Earvin “Magic” Johnson and Quincy Jones, who said “The heaviness of my heart today is unlike any other that I have ever experienced."