According to The Associated Press, Unser died Thursday at his New Mexico home following a 17-year battle with cancer. His wife, Susan, was with him when he died, the news agency reported.
The legendary driver won the Indy 500 in 1970, 1971, 1978 and 1987. Only three other drivers – A.J. Foyt, Rick Mears and Helio Castroneves – have logged four wins in the race, according to the AP.
News of Unser’s death came just months after his brother, fellow Indy 500 champion Bobby Unser, died in May at age 87, the AP reported. Bobby Unser’s son, Bobby Unser Jr., died the following month at age 65, according to the Albuquerque Journal.
Castroneves and Takuma Sato, who won the Indy 500 twice, took to social media overnight to pay tribute to Al Unser.
“RIP AL SR … you will b missed!” Castroneves captioned an Instagram post.
“Rest In Peace an incredible three time @IndyCar champion and four time #INDY500 winner Al Unser,” Sato tweeted. “It was my absolute honor to attend his baby @BorgTrophy ceremony. His speech was very funny and so charming. Huge respect. My deepest condolences to his family.”
In addition to his wife, Unser is survived by his son, two-time Indy 500 winner Al Unser Jr., the AP reported. Two daughters, Mary and Deborah, preceded him in death.
Photos: Al Unser through the years Four-time Indianapolis 500 winner Al Unser died Thursday, Dec. 9, 2021, at age 82, Indianapolis Motor Speedway confirmed. Here are some memorable photos of Unser through the years. (AP Photo/Doug McSchooler, File)
Photos: Al Unser through the years 1968: Al Unser Sr. poses with the Cotton Owens Dodge he drove to a fourth-place finish in the Daytona 500 at Daytona International Speedway in 1968. (ISC Images & Archives via Getty Images)
Photos: Al Unser through the years 1969: Driver Al Unser Sr. (left) and promoter-car owner J.C. Agajanian share a moment at an Indy Car race at Phoenix International Raceway in 1969. (ISC Images & Archives via Getty Images)
Photos: Al Unser through the years 1970: Al Unser Sr. in action in the Indianapolis 500 at Indianapolis Motor Speedway on May 31, 1970. (Tony Triolo/Sports Illustrated via Getty Images)
Photos: Al Unser through the years 1978: Formula 1 race car driver Al Unser waves three fingers in Victory Lane at Indianapolis Motor Speedway after winning the 62nd Indianapolis 500 in Indianapolis on May 28, 1978. (AP Photo, File)
Photos: Al Unser through the years 1986: Race car driver Al Unser Sr. prepares to board his car and compete in the 1986 IROC (International Race of Champions) at the Daytona International Speedway on February 16, 1986, in Daytona Beach, Florida. (Robert Alexander/Archive Photos/Getty Images)
Photos: Al Unser through the years 1987: Roberto Guerrero (4) in action, leading the Indianapolis 500 race against Al Unser Sr. (25) at Indianapolis Motor Speedway on May 24, 1987. (Ronald C. Modra/Sports Illustrated via Getty Images)
Photos: Al Unser through the years 1993: Formula 1 race car driver Al Unser is seen in 1993. (AP Photo, File)
Photos: Al Unser through the years 2006: Al Unser Sr. during Starkey Hearing Foundation's 2006 "So the World May Hear" Awards Gala at RiverCentre in St. Paul, Minnesota, on June 17, 2006. (Adam Bettcher/WireImage for Starkey Hearing Foundation)
Photos: Al Unser through the years 2016: Pro Indy Drivers Mario Andretti (left), Michael Andretti, Al Unser Sr. and Scott Dixon attend an "Evening With Legends" Q&A at the Petersen Automotive Museum on April 13, 2016, in Los Angeles. (Paul Archuleta/Getty Images)
Photos: Al Unser through the years 2021: Winner of the 2021 Indy 500, Helio Castroneves, right, gathered with other four-time winners, from left, A.J. Foyt (1961, 1964, 1967, 1977), Al Unser (1970, 1971, 1978, 1987) and Rick Mears (1979, 1984, 1988, 1991) at the Indianapolis Motor Speedway in Indianapolis on Tuesday, July 20, 2021. (AP Photo/Doug McSchooler, File)