The series formed in 1968 under the name "Grand Touring" as a competitor to USAC's Stock Car Division and SCCA's Trans-Am Series. It held 19 events in 1968 and 35 events in 1969. It was renamed Grand American for the 1970 season, hosting 27 events. By the 1971 season, NASCAR saw a decline in sponsorship, fan attendance and participation by teams, with Grand American hosting only seven events and NASCAR occasionally inviting Grand American cars to Grand National events that were short on entries (after the embarrassment of only 14 cars entering Grand National's 1971 Space City 300).
In 1972, the structure of NASCAR was completely changed. Winston took title sponsorship for the Grand National Series, which was renamed the Winston Cup Series. The extensive Grand National 48-race schedule of previous seasons was reduced to 31 by having all races at tracks under a 1/2 mile in length or 250 miles in event length moved to a new division called the Grand National East Division. Grand American and retired (as old as 1969) Grand National/Winston Cup cars were allowed to race in the new division. That series lasted from 1972 until 1973. The Grand American series held four events in 1972, its final season.
The series featured Ford Mustangs, Chevrolet Camaros, AMC Javelins, Mercury Cougars and Pontiac Trans Ams. Several Grand American cars were former SCCA Trans-Am cars, extensively modified to meet the NASCAR safety rules and weight limits.
The motors were initially restricted to a 305 cubic inch (5.0 liter) engine displacement. The 305 cubic inch limit eventually was increased to 366 cubic inch to help with performance and reliability of the Grand American cars.
In 1971, the money invested in NASCAR teams by American auto makers began to lessen as marketing and perceived consumer demand caused funds to shift away from NASCAR. The car entries for some of the top division Grand National events with smaller payouts shrank (only 14 cars entered the 1971 Space City 300) to the point that NASCAR allowed the Grand American cars to compete in certain Grand National races. Three of these Grand National races were won by drivers in Grand American cars; Tiny Lund (driving a Camaro in the Buddy Shuman 276 and the Wilkes 400) and Bobby Allison (driving a Mustang in the Myers Brothers 250) used pony cars at flat tracks that favored the smaller cars. These victories have not been added to either driver's NASCAR Grand National total wins and there is a debate whether or not they should be added.NASCAR had dictated that if a Grand American car won it would not be credited with the victory; first place points would not be awarded. Despite this, the wins were counted in the constructor's standings and as a start for Lund.
The series was dominated by Tiny Lund. Lund won 41 races in the 109 races in the series' history. Lund won three of the four full-season championships, with the other one won by Ken Rush of High Point, N.C. Pete Hamilton won 12 of 26 events in 1969.
Other notable drivers who were regular competitors in the Grand American Series include: Jim Paschal, Buck Baker and Richard Childress. Dan Gurney, Parnelli Jones, Mark Donohue and Jim Hall are sometimes credited as "NASCAR Grand American" drivers. The reality is that these road race stars competed in the SCCA Trans-Am series, which had at least one annual event co-sanctioned with NASCAR, the Florida Citrus 250 at Daytona. 
1969 championship results
- 1. Tiny Lund: 1,947 points - 9 wins (Mercury Cougar)
- 2. Buck Baker: 1,017 points - 3 wins (Chevrolet Camaro)
- 3. Jack Ryan: 1,012 points - 0 wins (Porsche 911)
- 4. Jim Vandiver: 938 points - 0 wins
- 5. Roy Tyner: 881 points - 0 wins
- 6. Al Straub: 875 points - 0 wins
- 7. Billy Yuma: 710 points - 0 wins
- 8. Ernie Shaw: 682 points - 0 wins
- 9. Donnie Allison: 664 points - 5 wins
- 10. Little Bud Moore: 653 points - 0 wins