Mario Andretti was born in Montona, Istria, Kingdom of Italy (present-day Motovun, Croatia) to Alvise “Gigi” Andretti and Rina Andretti. He was born six hours before his twin brother, Aldo. The Andretti family owned a 2,100-acre farm in Montona, but lost their land after World War II when the territory was transferred to communist-controlled Yugoslavia. The family joined the Istrian–Dalmatian exodus in 1948, spending seven years in a refugee camp in Lucca, Italy, living in an abandoned college dormitory. The Andretti family emigrated to Nazareth, Pennsylvania in 1955.
Andretti began dirt track racing with his twin brother Aldo in 1959. He progressed to USAC Championship Car racing in 1964, debuting at Trenton. In 1965, Andretti won his first USAC titles, taking the championship after finishing third at the Indianapolis 500. He also won the Indianapolis 500 in 1969, driving the team’s backup car after a mechanical issue. In 1967, Andretti won the Daytona 500, driving for Holman-Moody. That same year, he took his first major sportscar racing victory at the 12 Hours of Sebring with Ford.
Andretti won back-to-back USAC titles in 1965 and 1966, dominating the series with eight wins in 1966. He finished runner-up in 1967 and 1968. In 1970, Andretti took his maiden podium at the Spanish Grand Prix with STP, driving a privateer March 701, and signed with Ferrari that year. He took his maiden Formula One victory at the 1971 South African Grand Prix, driving for Ferrari. He won his third Sebring race in 1972.
In 1976, Andretti rejoined Lotus, winning the season-ending Japanese Grand Prix. He won four Grands Prix in 1977, finishing third in the World Drivers' Championship. He won the 1978 Formula One World Drivers' Championship with Lotus, achieving six victories. After winless 1979 and 1980 campaigns with Lotus, he moved to Alfa Romeo in 1981.
At the 1967 Indianapolis 500, Andretti qualified on pole but lost a wheel during the race. In 1987, Andretti led 170 of the first 177 laps of the Indianapolis 500 but his engine failed. In 1993, a pit stop error cost him a likely win at the Indianapolis 500.
Andretti retired from Formula One after two fill-in appearances for Williams and Ferrari in 1982. He continued to race in IndyCar until 1994, winning his final race at Phoenix in 1993 at the age of 53, making him the oldest winner in IndyCar history.
Andretti won over 100 races on major circuits, with the exact number varying depending on the definition of a major circuit. He stands alone as the only driver to win the Indianapolis 500, Daytona 500, and the Formula One World Drivers' Championship. He is one of only two drivers to have won races in Formula One, IndyCar, the World Sportscar Championship, and NASCAR. He holds the record for most laps led in IndyCar racing, with 7,595.
Andretti competed in sports car racing, winning three 12 Hours of Sebring races (1967, 1970, 1972). He also competed at the 24 Hours of Le Mans in four decades, finishing third in 1983.
Andretti was named Driver of the Century by the Associated Press (1999) and RACER magazine (2000). He was inducted into the International Motorsports Hall of Fame in 2000, the Indianapolis Motor Speedway Hall of Fame in 1986, and the Motorsports Hall of Fame of America in 1990. He serves on the board of directors of Cadillac in Formula One from its debut in 2026 onwards.