The story of IMSA begins in the late 1960’s. John Bishop was the Executive Director of the Sports Car Club of America (SCCA). Bill France was looking to develop an organization that could bring the same level of competitor and fan-friendly professionalism to sports car racing that NASCAR had instilled in stock car racing in the 40’s and 50’s.

At France’s invitation, Bishop traveled to Florida to meet face to face with Mr. France. “Bill said he thought there was a need for a new organization and he thought I might be the person to run it.” Bishop and France founded the International Motor Sports Association (IMSA) in 1969.

Articles of incorporation for the International Motor Sports Association (IMSA) were filed in Connecticut. John Bishop began a 20-year stint as IMSA President, while Peggy Bishop managed IMSA staff, registration, timing and scoring and other essential processes.

The first IMSA-sanctioned race – a Formula Ford and Formula Vee event – was held at Pocono International Raceway. Jim Clarke of Garden City, Michigan was the winner of the first Formula Ford race.

The first IMSA GT race – the Danville 300 – is held at Virginia International Raceway. Peter Gregg and Hurley Haywood co-drive the No. 59 Brumos Porsche 914/6 to victory.

Hurley Haywood wins his second consecutive IMSA GT championship.

Peter Gregg and Hurley Haywood co-drive to their first Rolex 24 At Daytona victory in the No. 59 Brumos Porsche 911 Carrera RSR. It was the first of six consecutive Rolex 24s where either Gregg or Haywood (or both) would be part of the overall winning driver lineup.

The first IMSA-sanctioned Twelve Hours of Sebring is held. Peter Gregg and Hurley Haywood team with Dave Helmick to win the race in the No. 59 Brumos Porsche and successfully sweep the “36 Hours of Florida.

The first IMSA partnership with the Automobile Club de l’Ouest (ACO) is formed between IMSA President John Bishop and ACO Technical Director Alain Bertaut, allowing for the exchange of cars between the 24-hour races at Daytona and Le Mans. It ultimately led to the creation of a joint set of prototype car regulations called GTP in 1980.

Al Holbert teams with Elliott Forbes-Robinson to win a six-hour IMSA race at Michelin Raceway Road Atlanta, co-driving the No. 14 Porsche Carrera RSR. It was Holbert’s first professional race.

The first IMSA-sanctioned Rolex 24 At Daytona is conducted at Daytona International Speedway. Hurley Haywood and Peter Gregg claim victory in the No. 59 Brumos Porsche

Al Holbert wins the IMSA GTO and GT Challenge titles, his first IMSA championships.

Hurley Haywood teams with John Graves and Dave Helmick to win the Rolex 24 At Daytona in the No. 43 Porsche 911 Carrera RSR. Four month later, Haywood became the first driver to win the 24-hour races at Daytona and Le Mans in the same year. Haywood would go on to win Le Mans three times (also winning in 1983 and 1994).

Peter Gregg wins his sixth and final IMSA GTO championship. He passed away on Dec. 15, 1980.

Hurley Haywood and Al Holbert combine with Bruce Leven to win the Twelve Hours of Sebring in the No. 86 Bayside Disposal Racing Porsche 935. It is the second overall Sebring victory for both Haywood and Holbert.

The Mazda RX-7 claims its first of seven consecutive IMSA GTU titles. Lee Mueller takes the IMSA GTU driver championship in an RX-7.

The Porsche 962 makes its IMSA debut in the Rolex 24 At Daytona. Mario Andretti qualified the No. 1 Porsche on the pole position.

The Porsche 962 claims its first IMSA victory in the Lumberman’s 500 at Mid-Ohio Sports Car Course. Co-drivers Al Holbert and Derek Bell accomplished the feat in the No. 14 Holbert Racing entry.

A.J. Foyt, Bob Wollek and Al Unser team up to record the first Rolex 24 At Daytona victory for the Porsche 962 in the No. 8 Henn’s Swap Shop machine. It was the first of three consecutive victories for the venerable 962 model in the twice-around-the-clock classic.

Scott Pruett records his first IMSA race victory at Pocono Raceway. He co-drove the No. 77 Brooks Racing Ford Thunderbird with Darin Brassfield to win the GTO class.

Jack Baldwin claimed IMSA GTU titles in both 1984 and 1985. The ’85 title was the fifth consecutive for a Mazda RX-7 driver, following Lee Mueller (1981), Jim Downing (1982) and Roger Mandeville (1983).

Al Holbert wins his second consecutive IMSA GTP title. It was his seventh and final IMSA championship. That same year, Scott Pruett claims his first IMSA titles, taking GTO and GT Endurance championships.

Scott Pruett claims his first Rolex 24 At Daytona class victory. He co-drove the No. 11 Roush Racing Ford Mustang with Tom Gloy, Bill Elliott and Lyn St. James to win the GTO class.

Al Holbert earns his 49th and final overall victory in IMSA competition in the three-hour Grand Prix of San Antonio, co-driving the No. 14 Holbert Racing Porsche 962 HR1 with Chip Robinson and Derek Bell. To date, no driver has earned more overall victories in IMSA competition than Holbert. The following year, on Sept. 30, 1988, Holbert died in a plane crash near Columbus, Ohio.

As Jack Baldwin had done two years prior, Tommy Kendall scored back-to-back IMSA GTU championships in 1986 and 1987, running the Mazda RX-7’s championship winning streak to seven.

Rethinking priorities due to health, John and Peggy Bishop sold IMSA to Mike Cone and Jeff Parker, owners of the Tampa World Challenge event at the time.

Hurley Haywood earns his record fifth overall victory in the Rolex 24 At Daytona. He co-drove to the win with Frank Jelinski, Henri Pescarolo, Bob Wollek and John Winter in the No. 7 Porsche 962C. It was also the fifth and final Rolex 24 victory for the Porsche 962.

Scott Pruett earns his first overall victory in the Rolex 24 At Daytona. He co-drove the No. 76 Cunningham Nissan 300ZX to the win alongside Butch Leitzinger, Paul Gentilozzi and Steve Millen.

Jay Cochran drives the No. 50 Euromotorsport Ferrari 333 SP to victory in its debut race at Michelin Raceway Road Altanta. Cochran led a 1-2 sweep for the new cars from Maranello, besting Gianpiero Moretti and Eliseo Salazar in the No. 30 MOMO Ferrari.

South Florida businessman Charlie Slater, who previously owned a medical equipment company, Symbiosis Corporation, acquired IMSA.

Fermin Velez delivered the first IMSA championship for the Ferrari 333 SP. He won three races and finished on the podium eight times in the 11-race season to take home the title in the Scandia Racing-entered machine. Ferrari also won the WSC manufacturer championship.

After two years Charlie Slater sold IMSA to a new group led by team owner Andy Evans and former Reebok CEO Roberto Muller. Evans’ renamed the organization Professional Sports Car Racing (PSCR).

Disenchanted by PSCR, a group of racing luminaries including John Bishop, Bill France Jr., Nick Craw; team owners like Roger Penske, Rob Dyson, Jim Downing and Bob Snodgrass; and a number of race promoters joined forces to create the United States Road Racing Championship (USRRC). The series was run by the Sports Car Club of America (SCCA) and featured the Rolex 24 At Daytona as its signature event.

Mauro Baldi, Gianpiero Moretti and Didier Theys win the Twelve Hours of Sebring in their Doran/Moretti Racing Ferrari 333 SP. The victory comes less than two months after the same trio combined with Indy 500 winner Arie Luyendyk to win the Rolex 24 At Daytona.

Don Panoz created a partnership with the ACO to begin a 10-hour race in the spirit of Le Mans to be held at Panoz’s Michelin Raceway Road Atlanta. The first Motul Petit Le Mans is won overall by Eric van de Poele, Emmanuel Collard and Wayne Taylor in a Ferrari 333 SP, the final IMSA win for the venerable race car.

Bolstered by the success of the inaugural Petit Le Mans in 1998, Don Panoz buys out PSCR and launches the American Le Mans Series (ALMS) using the fundamental concepts of the rules developed by the Automobile Club de l’Ouest (ACO) for the 24 Hours of Le Mans. Panoz changes PSCR’s name back to IMSA and Scott Atherton becomes president of the ALMS.

The American Le Mans Series (ALMS) makes its debut at the Twelve Hours of Sebring. Jorg Muller, JJ Lehto and Tom Kristensen took the victory in the No. 42 BMW V12 LMR.

After the final two rounds of the 1999 USRRC season are canceled, Jim France founds the GRAND-AM Road Racing Association. Former American Motorcyclist Association (AMA) president Roger Edmondson becomes the first president of GRAND-AM.

The GRAND-AM Rolex Sports Car Series debuts with the Rolex 24 At Daytona. Olivier Beretta, Karl Wendlinger and Dominique Dupuy won the race in the No. 91 Dodge Viper GTS-R.

The Corvette C5-R scores its first IMSA victory in the Grand Prix of Texas. Ron Fellows and Andy Pilgrim delivered the GTS class win in the No. 3 Corvette.

Ron Fellows, Chris Kneifel and Franck Freon co-drive the No. 2 Corvette C5-R to the overall victory in the Rolex 24 At Daytona. Finishing second in the GTS class and fourth overall were their teammates in the No. 3 Corvette, Andy Pilgrim, Kelly Collins, Dale Earnhardt Jr. and Dale Earnhardt.

The Corvette C5-R earns its first Twelve Hours of Sebring victory. Ron Fellows, Johnny O’Connell and Oliver Gavin did the honors, taking the GTS-1 class win in the No. 3 machine.

The Corvette C5-R records its 32nd and final IMSA race victory with Ron Fellows and Johnny O’Connell at the controls of the No. 3 entry at WeatherTech Raceway Laguna Seca.

NASCAR Holdings announced an agreement to acquire the GRAND-AM Road Racing Association, allowing for resource sharing between GRAND-AM and NASCAR while both organizations continued to operate independently.

In an historic press conference at Daytona International Speedway, GRAND-AM founder Jim France and American Le Mans Series founder Don Panoz announced that GRAND-AM Road Racing would merge with the International Motor Sports Association – combining ALMS and the GRAND-AM Rolex Series into one premier sports car series debuting in 2014.

Scott Pruett wins his fifth GRAND-AM Rolex Series Daytona Prototype (DP) championship. The following year, he won the GRAND-AM North American Endurance Cup title, his ninth and final IMSA championship.

Scott Pruett co-drives with Memo Rojas, Juan Pablo Montoya and Charlie Kimball in the No. 01 Chip Ganassi Racing with Felix Sabates BMW Riley to earn his fifth overall victory in the Rolex 24 At Daytona. The victory ties Pruett with Hurley Haywood for most overall wins in race history, and was Pruett’s 10th Rolex 24 class victory, which stands as the all-time record.

Scott Pruett earns his 60th and final IMSA race victory alongside co-driver Joey Hand in the No. 01 Chip Ganassi Racing Ford EcoBoost Riley DP at Circuit of The Americas. Pruett retired from IMSA competition following the 2018 Rolex 24 At Daytona, as the winningest IMSA driver of all time. Since Pruett’s retirement, Bill Auberlen eclipsed Pruett’s IMSA win total.