| Date | Overall winner(s) | Entrant | Car | Distance/Duration | Race title | Report |
| SCCA National Sports Car Championship |
| 1955 |
Phil Hill | George E. Tilp | Ferrari 750 Monza | 150 miles (240 km) | Elkhart Lake's Road America Road Race | report |
| 1956 |
John Kilborn
Howard Hively | John Kilborn | Ferrari 375 MM | 6 hours | Road America 6 Hours | report |
| 1957 |
Phil Hill | Gene Greenspun | Ferrari 315 S | 500 miles (800 km) | Road America 500 | report |
| 1958 |
Gaston Andrey
Lance Reventlow | North American Racing Team | Ferrari 335 S | 500 miles (800 km) | Road America 500 | report |
| 1959 |
Ed Crawford
Walt Hansgen | Briggs Cunningham | Lister - Jaguar | 500 miles (800 km) | Road America 500 | report |
| 1960 |
Dave Causey
Luke Stear | Dave Causey | Maserati Tipo 61 | 500 miles (800 km) | Road America 500 | report |
| 1961 |
Walt Hansgen
Augie Pabst | Briggs Cunningham | Maserati Tipo 63 | 500 miles (800 km) | Road America 500 | report |
| 1962 |
Jim Hall
Hap Sharp | Jim Hall | Chaparral 1-Chevrolet | 500 miles (800 km) | Road America 500 | report |
| United States Road Racing Championship |
| 1963 |
Augie Pabst
Bill Wuesthoff | Porsche Car Import/Oliver Schmidt | Elva Mk.7-Porsche | 500 miles (800 km) | Road America 500 | report |
| 1964 |
Walt Hansgen
Augie Pabst | John Mecom Jr. | Ferrari 250 LM | 500 miles (800 km) | Road America 500 | report |
| 1965 |
Jim Hall
Hap Sharp
Ronnie Hissom | Jim Hall | Chaparral 2A-Chevrolet | 500 miles (800 km) | Road America 500 | report |
| 1966 |
Chuck Parsons | Randy Hilton | McLaren Elva Mk.II-Chevrolet | 500 miles (800 km) | Road America 500 | report |
| 1967 |
Chuck Parsons
Skip Scott | Carl Haas | McLaren Elva Mk.III-Chevrolet | 500 miles (800 km) | Road America 500 | report |
| 1968 |
Chuck Parsons
Skip Scott | Carl Haas | Lola T70 Mk.3-Chevrolet | 500 miles (800 km) | Road America 500 | report |
| 1969–1978: Not held |
| IMSA GT Championship |
| 1979 |
David Hobbs
Derek Bell | McLaren North America | BMW 320i Turbo | 500 miles (800 km) | Pabst 500 | report |
| 1980 |
John Paul Jr.
John Paul Sr. | JLP Racing | Porsche 935 JLP-2 | 500 miles (800 km) | Pabst 500 | report |
| 1981 |
Rolf Stommelen
Harald Grohs | Andial Meister Racing | Porsche 935 K3 | 500 miles (800 km) | Pabst 500 | report |
| 1982 |
John Fitzpatrick
David Hobbs | John Fitzpatrick Racing | Porsche 935 K4 | 500 miles (800 km) | Pabst 500 | report |
| 1983 |
Klaus Ludwig
Tim Coconis | Zakspeed | Ford Mustang GTP | 460 miles (740 km) A | Pabst 500 | report |
| 1984 |
Al Holbert
Derek Bell | Holbert Racing | Porsche 962 | 500 miles (800 km) | Budweiser 500 | report |
| 1985 |
Drake Olson
Bobby Rahal | Dyson Racing | Porsche 962 | 500 miles (800 km) | Löwenbräu Classic | report |
| 1986 |
Al Holbert
Al Unser Jr. | Holbert Racing | Porsche 962 | 500 miles (800 km) | Löwenbräu Classic | report |
| 1987 |
Price Cobb
Johnny Dumfries | Dyson Racing | Porsche 962 | 500 miles (800 km) | Löwenbräu Classic | report |
| 1988 |
Geoff Brabham
John Morton | Electramotive Engineering | Nissan GTP ZX-T | 500 km (310 mi) | Miller High Life 500 | report |
| 1989 |
Geoff Brabham
Chip Robinson | Electramotive Engineering | Nissan GTP ZX-T | 500 km (310 mi) | Miller High Life 500 | report |
| 1990 |
Geoff Brabham | Nissan Performance | Nissan NPT-90 | 250 km (160 mi)B | Chicago Tribune presents the Nissan Grand Prix of Road America | report |
| 1991 |
Davy Jones | Bud Light/Jaguar Racing | Jaguar XJR-16 | 300 km (190 mi)C | Nissan Grand Prix of Road America | report |
| 1992 |
Juan Manuel Fangio II | All American Racers | Eagle Mk III Toyota | 2 hours | Nissan Grand Prix of Road America | report |
| 1993 |
John Winter
Manuel Reuter | Joest Porsche Racing | Porsche 962C | 500 km (310 mi) | Piggly Wiggly Grand Prix 500 Kilometers | report |
| 1994–1999 Not held |
| Grand American Road Racing Championship |
| 2000 |
Didier Theys
Fredy Lienhard
Mauro Baldi | Doran Lista Racing | Ferrari 333 SP-Judd | 500 miles (800 km) | Sargento Road America 500 | report |
| 2001 |
Didier Theys
Fredy Lienhard
Mauro Baldi | Lista Doran Racing | Ferrari 333 SP-Judd | 500 miles (800 km) | Sargento Road America 500 | report |
| American Le Mans Series |
| 2002 |
Tom Kristensen
Rinaldo Capello | Audi Sport North America | Audi R8 | 4 hours, 15 minutes | Road America 500 presented by the Chicago Tribune | report |
| 2003 |
Johnny Herbert
JJ Lehto | ADT Champion Racing | Audi R8 | 2 hours, 45 minutes | Road America 500 presented by the Chicago Tribune | report |
| 2004 |
JJ Lehto
Marco Werner | ADT Champion Racing | Audi R8 | 2 hours, 45 minutes | Road America 500 presented by the Chicago Tribune | report |
| 2005 |
Frank Biela
Emanuele Pirro | ADT Champion Racing | Audi R8 | 2 hours, 45 minutes | Generac 500 | report |
| 2006 |
Frank Biela
Emanuele Pirro | Audi Sport North America | Audi R10 TDI | 2 hours, 45 minutes | Generac 500 | report |
| 2007 |
Romain Dumas
Timo Bernhard | Penske Racing | Porsche RS Spyder | 4 hours | Generac 500 | report |
| 2008 |
Lucas Luhr
Marco Werner | Audi Sport North America | Audi R10 TDI | 4 hours | Generac 500 | report |
| 2009 |
Scott Sharp
David Brabham | Patrón Highcroft Racing | Acura ARX-02a | 2 hours, 45 minutes | Time Warner Cable Road Race Showcase | report |
| 2010 |
Paul Drayson
Jonny Cocker | Drayson Racing | Lola B09/60 | 2 hours, 45 minutes | American Le Mans Series powered by eStar | report |
| 2011 |
Klaus Graf
Lucas Luhr | Muscle Milk Aston Martin Racing | Lola-Aston Martin B08/62 | 4 hours | Time Warner Cable Road Race Showcase | report |
| 2012 |
Chris Dyson
Guy Smith | Dyson Racing | Lola B12/60-Mazda | 4 hours | Road America Road Race Showcase | report |
| 2013 |
Klaus Graf
Lucas Luhr | Muscle Milk Pickett Racing | HPD ARX-03c-Honda | 2 hours, 45 minutes | Orion Energy Systems 245 | report |
| IMSA SportsCar Championship |
| 2014 |
João Barbosa
Christian Fittipaldi | Action Express Racing | Coyote Corvette DP Chevrolet | 2 hours, 45 minutes | Continental Tire Road Race Showcase | report |
| 2015 |
Dane Cameron
Eric Curran | Action Express Racing | Coyote Corvette DP Chevrolet | 2 hours, 40 minutes | Continental Tire Road Race Showcase | report |
| 2016 |
Dane Cameron
Eric Curran | Action Express Racing | Coyote Corvette DP Chevrolet | 2 hours, 40 minutes | Continental Tire Road Race Showcase | report |
| 2017 |
Pipo Derani
Johannes van Overbeek | Tequila Patrón ESM | Nissan Onroak DPi | 2 hours, 40 minutes | Continental Tire Road Race Showcase | report |
| 2018 |
Jon Bennett
Colin Braun | CORE Autosport | Oreca 07 | 2 hours, 40 minutes | Continental Tire Road Race Showcase | report |
| 2019 |
Jonathan Bomarito
Harry Tincknell | Joest Racing | Mazda RT24-P | 2 hours, 40 minutes | Road Race Showcase at Road America | report |
| 2020 |
Hélio Castroneves
Ricky Taylor | Team Penske | Acura ARX-05 | 2 hours, 40 minutes | IMSA SportsCar Weekend | report |
| 2021 |
Pipo Derani
Felipe Nasr | Action Express Racing | Cadillac DPi-V.R | 2 hours, 40 minutes | IMSA SportsCar Weekend | report |
| 2022 |
Filipe Albuquerque
Ricky Taylor | WTR - Konica Minolta Acura | Acura ARX-05 | 2 hours, 40 minutes | IMSA Fastlane SportsCar Weekend | report |
| 2023 |
Matt Campbell
Felipe Nasr | Porsche Penske Motorsport | Porsche 963 | 2 hours, 40 minutes | IMSA SportsCar Weekend | report |
| 2024 |
Nick Tandy
Mathieu Jaminet | Porsche Penske Motorsport | Porsche 963 | 2 hours, 40 minutes | IMSA SportsCar Weekend | report |
| 2025 |
Philipp Eng
Dries Vanthoor | BMW M Team RLL | BMW M Hybrid V8 | 2 hours, 40 minutes | Motul SportsCar Grand Prix | report |
| 2026 |
Filipe Albuquerque
Ricky Taylor | Cadillac Wayne Taylor Racing | Cadillac V-Series.R | 6 hours | Motul SportsCar Endurance Grand Prix | report |