USAC was formed after the American Automobile Association (AAA) withdrew from auto racing following the 1955 season, citing the Le Mans disaster and the death of Bill Vukovich at Indianapolis as contributing factors. USAC became the arbiter of rules and car design for championship auto racing, its highest level of competition. Initially, there were separate specifications for championship cars designed for dirt tracks versus paved tracks.
The "triple crown" in USAC racing is achieved when a driver wins all three national championships: Silver Crown, sprint car, and midget car. Only two drivers, Tony Stewart (1995) and J. J. Yeley (2003), have accomplished this feat in a single season. Six other drivers—Pancho Carter (1972–78), Dave Darland (1997–2001), Jerry Coons Jr. (2006–08), Tracy Hines (2000, 2002, 2015), Chris Windom (2016, 2017, 2020), and Logan Seavey (2023–2024)—have claimed each of the three championships at least once in their careers. In 2012, Mike Curb and Cary Agajanian became the only car owners to win all three championships in the same year.
USAC awarded a national championship until A. J. Foyt won his seventh title in 1979. The championship resumed in 2010, with a driver's best 25 finishes from the sprint, midget, and Silver Crown series counting toward the title. Bryan Clauson of Noblesville, Indiana, claimed the inaugural 2010 championship, topping Levi Jones by 14 points, and also won in 2011 and 2012. As of 2013, the award has been known as the Mike Curb "Super License" National Championship Award. Tracy Hines won the championship in 2013 and 2014, followed by Dave Darland in 2015, Brady Bacon in 2016, Justin Grant in 2017, Tyler Courtney in 2018 and 2019, Chris Windom in 2020, Justin Grant again from 2021 to 2023, and Logan Seavey in 2024.
On April 23, 1978, a plane crash killed eight USAC officials and the pilot while returning from a race at Trenton Speedway in New Jersey. The 10-seat Piper Navajo Chieftain crashed during a thunderstorm 25 miles southeast of Indianapolis. Those killed included Ray Marquette, USAC's vice-president of public affairs; Frank Delroy, chairman of the technical committee; Shim Malone, starter and head of the midget racer division; Judy Phillips, graphic artist and publication director; Stan Worley, chief registrar; Ross Teeguarden, assistant technical chairman; Don Peabody, head of the sprint division; Dr. Bruce White, assistant staff doctor; and Don Mullendore, the plane's owner and pilot. Arthur W Graham III, Director of Timing & Scoring, was scheduled for the flight but drove back with timing equipment instead. This incident occurred shortly after the death of Indianapolis Motor Speedway owner Tony Hulman.
The plane crash occurred during a period of growing dissent among Indy car owners and drivers regarding USAC's management. Owners felt that USAC poorly negotiated television rights, leading to low attendance at events outside the Indianapolis 500, and demanded increased payouts, particularly at Indy. While some have suggested the crash was used to force changes in the sport, the seeds of dissent had been present for several years prior, and claims that the crash was an immediate cause for the 1979 CART/USAC "split" are largely considered unfounded.
USAC's attempts to keep the aging Offenhauser engine competitive with the newer Cosworth DFX engine through boost-limiting "pop off valves" and fuel limits were also unpopular. In 1978, most car owners formed Championship Auto Racing Teams (CART), with their first race scheduled for 1979. USAC's attempt to ban CART owners from the 1979 Indianapolis 500 was unsuccessful, losing in court before the race. Both USAC and CART ran multi-race schedules in 1979.
In March 1980, Indianapolis Motor Speedway president John Cooper helped form a joint body, the Championship Racing League (CRL), between CART and USAC. However, Cooper later forced USAC to renounce this agreement to retain officiating rights for the Indy 500. After a USAC-sanctioned 500-mile race at Pocono Raceway was boycotted by CART teams, USAC and CART settled into a co-existence. USAC continued to sanction only the Indianapolis 500, which was included in CART's schedule. When the Indy Racing League (IRL) split from CART in 1996, USAC sanctioned IRL races, including the Indy 500, until its sanctioning agreement was terminated following officiating errors at the 1997 Indianapolis 500 and 1997 True Value 500. Subsequent Indy 500s have been sanctioned by the IRL, which was renamed the IndyCar Series in 2003.
Since 2022, USAC has expanded its sanctioning to include road racing series under its newly formed Road Racing Division, directed by Randy Hembrey. These include the USF Juniors, USF2000 Championship, and USF Pro 2000 Championship, which serve as a ladder series to Indy NXT. USAC also sanctions the Radical Sportscars North American Championships, Skip Barber Racing School, GT World Challenge America, and Porsche Sprint Challenge North America.
USAC currently sanctions several open-wheel, road racing, and off-road series.
The Silver Crown Series began in 1971 as the "National Dirt Car Championship," splitting dirt races from the National Championship. It was renamed the "Silver Crown Series" in 1981.
From 1956 to 1960, the National Sprint Car Championship was divided into Midwest and East regional divisions.
The USAC/CRA AMSOIL Sprint Car Series debuted in 2004, utilizing 410ci engines and cars similar to the National Sprint Car Championship, racing on dirt ovals in California and Arizona. It also features combination races with the AMSOIL USAC Sprint Car National Championship.
Started in 1982, the Western States Midget Series uses the same cars and engines as the USAC National Midgets. It primarily races on dirt ovals in California and Arizona, though it previously raced on pavement. The series runs co-sanctioned races with the USAC National Midget Series, including the Turkey Night Grand Prix, and the Bay Cities Racing Association Midgets.
USAC sanctions several regional 360 c.i.d. non-wing sprint car series. The West Coast Sprint Car Series, launched in 2009 by Santa Maria Speedway promoter Chris Kearns and joining USAC in 2010, primarily races in California and Nevada. The Southwest Sprint Car Series, launched in 1991 as the Arizona Sprint Car Racing Association and joining USAC in 2012, primarily raced in Arizona, Nevada, and New Mexico, with special events in Arkansas, Kansas, and Oklahoma, before being put on hold after the 2019 season. In 2018, USAC and URC Sprint Car Series promoter Curt Michael created the USAC East Coast Sprint Car Series.
Formed in 2002, the Speed2 Midget Series (formerly Ford Focus Midget Series, Ignite Midget Series, and HPD Midget Series) features regional divisions on dirt and pavement ovals across the United States. These cars use 4-cylinder production-based engines with stock internal dimensions for cost savings, differing from National and Western States Midget cars only in engine. The series began as a spec engine class, with Ford supplying Zetec engines from 2002 to 2012, and HPD supplying K24 engines starting in 2013.
The Speed2 Midget Series National Champion has been determined in various ways. The inaugural 2005 championship was decided by a two-race series (one dirt, one pavement). From 2006 to 2010, a single "national championship race" determined the winner. In 2011, a points system was instituted, counting a driver's twelve best finishes, allowing drivers from multiple regions to compete for a season-long championship. No national champion was awarded in 2012, though regional champions were honored. National Champions include Robbie Ray (2005), Michael Faccinto (2006), James Robertson (2007), Alex Bowman (2008), Kyle Hamilton (2009), and Nick Drake (2010, 2011).
USAC started the Speedway Motors Lightning Sprint National Championship in 2017 for local tracks running Lightning Sprint cars. The points format counts the 12 best races at USAC-sanctioned tracks.
Pirelli World Challenge, founded in 1990, switched to USAC sanctioning in 2017. The championship, owned by SRO Group, races on road and street courses across the United States and Canada, featuring seven different classes for GT and Touring cars.
USAC sanctions several off-road racing series. The Stadium Super Trucks series, founded in 2013 by Robby Gordon, is co-owned by Gordon and The Elevation Group. USAC also sanctions the American Rally Association, Nitro Rallycross, King of the Hammers, and Great American Shortcourse.
Beginning in 1981, USAC scaled back its involvement in Indy car racing outside the Indianapolis 500, with CART sanctioning the preeminent national championship. USAC developed a split-calendar Gold Crown season, starting in June and ending in May with the Indy 500. After 1983, the Gold Crown schedule consisted of only the Indy 500, making the winner of that race the de facto Gold Crown champion. The title and "series" were retired after the 1994–1995 season with the advent of the Indy Racing League.
USAC operated a stock car division from 1956 to 1984. The inaugural 1956 season featured two subtitles: Pacific Coast, won by Sam Hanks, and Short Track, won by Troy Ruttman.
From 1958 to 1962, USAC sanctioned a road racing championship. It was held for sports cars from 1958 to 1961 and adopted Formula Libre rules in 1962.
TORC: The Off-Road Championship was founded in 2009 by motocross racer Rick Johnson. USAC took over complete management of the series in 2010, but this ended in August 2013 when it was sold to The Armory. USAC returned to officiating and race control, and the series was renamed "TORC: The Off Road Championship" for 2014. Champions included Rick Huseman (2009 Pro 4x4), Rob MacCachren (2009 Pro 2WD), Johnny Greaves (2010, 2013, 2014 Pro 4x4), Ricky Johnson (2010, 2011, 2012 Pro 2WD; 2011, 2012 Pro 4x4), Bryce Menzies (2011, 2012, 2013 Pro 2WD), and CJ Greaves (2014 Pro 2WD).