Bernstein grew up in Lubbock, Texas, attending Monterey High School before enrolling at Arlington State College (now the University of Texas at Arlington) to study business administration. He left college in 1966 without graduating, initially working as a traveling salesman across the American South before pursuing drag racing full time. His path to the sport was unconventional; financial necessity kept him out of a cockpit for years before he could mount a credible professional effort.
Bernstein made his mark in the NHRA's Funny Car class, first appearing at the 1978 Summernationals at Englishtown, New Jersey, driving the Chelsea King funny car. He transitioned to full-time Funny Car competition in 1979 and shortly afterward secured one of the most significant sponsorship deals in drag racing history: a partnership with Anheuser-Busch's Budweiser brand that would last thirty years.
Working with tuner Dale Armstrong, Bernstein developed a reputation for aerodynamic innovation. In 1987, the pair commissioned the Arivett brothers — land speed record specialists — to design a Buick LeSabre-bodied funny car. The resulting machine, nicknamed the "Batmobile," introduced bodywork principles that fundamentally reshaped Funny Car aerodynamics across the sport. Bernstein won his first Funny Car championship in 1985 and successfully defended it over the following three seasons, claiming four consecutive titles.
In 1990, following an NHRA rules change, Bernstein moved to the Top Fuel Dragster class. Two years later, on March 20, 1992, at the Gatornationals in Gainesville, Florida, he became the first competitor in any racing class to officially exceed 300 mph in a standing-start quarter mile — a landmark moment in motorsport history. He captured the Top Fuel championship in 1996, becoming the first driver in NHRA history to win titles in both nitro categories. Bernstein himself later described that 1996 title as "somewhat tainted" following the fatal crash of fellow competitor Blaine Johnson during the season; at the year-end awards banquet, he presented his championship trophy to Johnson's brother Alan, who went on to become one of drag racing's most decorated crew chiefs.
Bernstein reclaimed the Top Fuel championship in 2001, making him the only driver in NHRA history to win multiple championships in both the Funny Car and Top Fuel classes.
Bernstein retired from full-time driving at the end of the 2002 season, handing the Budweiser King dragster to his son Brandon. The retirement was short-lived: Brandon Bernstein broke his back in June 2002, and Kenny returned as a substitute driver for the remainder of the season. Racing in only 15 events, he won four consecutive Top Fuel events to close out the year and finished sixth in season points.
In September 2006, Bernstein announced a second comeback, this time returning to Funny Car for the 2007 season with a Monster Energy Dodge Charger. The campaign was troubled from the start — he failed to qualify for the opening two events — and he did not make the inaugural Countdown to the Championship. After the season he stepped away from the cockpit permanently, hiring Tommy Johnson Jr. to drive the Monster Energy car for 2008 before discontinuing that team entirely.
Alongside his driving career, Bernstein operated King Racing as a NASCAR Cup Series team from 1986 to 1995 and ran King Motorsports as an IndyCar outfit concurrently. At the 1988 Indianapolis 500, his car, driven by Jim Crawford, led eight laps and finished sixth. Bernstein is the only team owner to record victories in NHRA drag racing, NASCAR, and IndyCar competition.
After Budweiser ended its sponsorship following the InBev acquisition of Anheuser-Busch, Bernstein signed Copart Inc. to back Brandon's dragster, later adding Lucas Oil for the 2011 season. On November 15, 2011, two days after the season's final race, Bernstein announced his full retirement from NHRA racing as both driver and team owner.
Beyond his racing achievements, Bernstein became a significant voice in NHRA safety reform. Following the crash deaths of Eric Medlen and Scott Kalitta, he worked alongside John Force, Tony Schumacher, and the NHRA Track Safety Committee to develop an engine monitoring sensor for Top Fuel dragsters and Funny Cars. The device detects engine backfires and automatically shuts off the fuel pump while simultaneously deploying the parachutes — a safety measure designed to prevent the type of catastrophic fuel fire that contributed to Kalitta's death at the 2008 SuperNationals.
Bernstein's career established benchmarks that defined the modern era of NHRA competition. His aerodynamic work with Armstrong and the Batmobile Funny Car shifted the entire field's design philosophy. His 300 mph barrier break in 1992 remains one of the most cited milestones in drag racing's history. The thirty-year Budweiser sponsorship — covering both Kenny and Brandon Bernstein — is widely regarded as one of the longest and most prominent driver-sponsor relationships in motorsports.
Bernstein was named sixth on the NHRA's list of the top 50 drivers from 1951 to 2000, inducted into the International Jewish Sports Hall of Fame in 2006, and enshrined in the Motorsports Hall of Fame of America in 2009. He served as president of the Professional Racers Organisation (PRO), a body representing NHRA drivers, mechanics, and team owners that advocates on safety and prize money issues.