Senna was born in the Santana neighbourhood of Sao Paulo into a wealthy family; his father Milton operated an automotive factory and a farm. He showed an early fascination with cars and engines, and his father built his first go-kart using a small lawnmower engine. Senna began kart racing at the age of 13, quickly establishing himself as a prodigious talent. He won the South American Kart Championship in 1977, and contested the Karting World Championship five times between 1978 and 1982, finishing runner-up in both 1979 and 1980. During that period his closest rival was Terry Fullerton, of whom Senna later said he got the most satisfaction racing against anyone because of the absence of money and politics — "pure racing."
In 1981 Senna moved to England to pursue open-wheel racing, dominating Formula Ford 1600 and then the Formula Ford 2000 series for Van Diemen. In 1983 he competed in the British Formula Three Championship for West Surrey Racing, winning the title after a close and at times contentious battle with Martin Brundle. That November he also won the inaugural Macau Formula Three Grand Prix.
Senna made his Formula One debut at the 1984 Brazilian Grand Prix with Toleman, a relatively small team running Pirelli tyres. His most memorable drive of that debut season came in the rain-soaked Monaco Grand Prix, where he climbed from 13th on the grid to second and was closing rapidly on race leader Alain Prost when the race was red-flagged on lap 31 — a controversial stoppage that denied him a likely victory. He finished the season ninth in the championship with 13 points after being suspended by Toleman late in the year for entering talks with Lotus without the team's knowledge.
At Lotus, Senna took his first Formula One pole position and victory at the 1985 Portuguese Grand Prix, winning in torrential rain by over a minute — a performance he later described as the best drive of his career. He was the standout qualifier of his era, accumulating seven poles in 1985 alone. In 1987, driving a Honda-powered Lotus, he took his first Monaco Grand Prix victory — the first of a record six wins at the Principality. He finished that season third in the championship with 57 points.
Senna joined McLaren in 1988 to partner Alain Prost, with Honda power providing the McLaren MP4/4 a dominant advantage. Together they won 15 of 16 races that season, with Senna taking eight victories to claim his first world title by three points. A fierce personal and sporting rivalry with Prost escalated over subsequent seasons.
In 1989, Prost won the title after a collision between the two at Suzuka that led to Senna's disqualification from the race. In 1990, Senna exacted deliberate revenge at the same corner — an act he admitted to a year later — to claim his second championship. In 1991 he won seven races and secured his third title, becoming at that time the youngest ever three-time champion.
The 1992 season brought Williams dominance; Senna won three races but finished fourth overall. In 1993, despite McLaren's inferior Ford-powered machinery, he won six races including a record sixth Monaco victory and produced one of his most celebrated drives at the European Grand Prix at Donington Park, overtaking four drivers on the opening lap in wet conditions and eventually lapping the field bar second place. He again finished runner-up to Prost in the championship. His 41st and final win came at the 1993 Australian Grand Prix — also McLaren's 104th constructor victory, placing it ahead of Ferrari in the all-time standings.
Senna joined Williams for 1994 to replace the retiring Prost. He was apprehensive about the Williams FW16 from the outset, and the car was unstable in the wake of the FIA's ban on electronic driver aids that season. He took pole positions at the opening three races but retired from each without scoring a point.
At the 1994 San Marino Grand Prix at Imola — a race weekend already shadowed by serious accidents to Rubens Barrichello and the fatal crash of Roland Ratzenberger during qualifying — Senna was killed when his car left the track at the high-speed Tamburello corner on lap 7. He was airlifted to Bologna's Maggiore Hospital and pronounced dead that evening. The crash was subsequently linked to a poorly modified steering column.
On the morning of the race Senna had spoken with Prost about reviving the Grand Prix Drivers' Association to improve safety, and was carrying an Austrian flag in the cockpit, reportedly intended as a tribute to Ratzenberger. His state funeral in Sao Paulo was attended by more than a million people, with the Brazilian government declaring three days of national mourning.
Senna's death catalysed sweeping safety reforms in Formula One: track redesigns, improved crash barriers, higher cockpit and helmet standards, and a reduction in engine power were among the immediate measures. The Tamburello corner at Imola was heavily modified for 1995. He remained the last fatality in the Formula One World Championship until Jules Bianchi in 2014.
Multiple polls by racing publications, driver cohorts, and statistical analyses have consistently ranked Senna as the greatest Formula One driver of all time, and he retains the highest ratio of wins in wet-weather races of any driver as of the mid-2020s. Before his death he quietly donated millions of dollars to programmes supporting Brazilian children; his family subsequently formalised this as the Instituto Ayrton Senna, which has invested nearly 80 million US dollars in educational and social programmes over the years since.
He was inducted into the International Motorsports Hall of Fame in 2000 and into the Automotive Hall of Fame in 2025. Lewis Hamilton, Fernando Alonso, Sebastian Vettel, and many other champions of subsequent generations have cited Senna as their primary inspiration in motorsport.