Marcis drove for series championship car owners Nord Krauskopf and Rod Osterlund during the peak years of his career before opting to field his own equipment. His best championship results came in the 1970s: second in 1975, fifth in 1978, and sixth in both 1974 and 1976. In 1975 he finished second in the standings driving Krauskopf's K&K Dodge Charger, the first year of NASCAR's modern points system. Former crew chief Harry Hyde once observed of Marcis that he "had the talent to be a champion, if only he weren't so stubborn."
When Marcis departed Osterlund Racing after the 1978 season — a team that subsequently hired Dale Earnhardt for his rookie campaign — he committed to running his own operation, typically under the No. 71 banner. The highlight of this independent period came at the old Richmond Fairgrounds in 1982, where Marcis won in an 81 Chevy Malibu despite being a lap down. He regained the lap when race leader Joe Ruttman spun; the drivers ahead then pitted as rain began, Marcis inherited the lead, and the race was called complete as darkness set in. He later described it as "one of my greatest moments in racing," noting he had built the engine himself. From that point his equipment gradually became less competitive relative to the growing investment of well-funded factory-backed teams.
Marcis competed in the Daytona 500 every year from 1968 through 1999, and his final NASCAR race was the 2002 Daytona 500. Over his career he ran 883 starts, retiring second on the all-time starts list behind Richard Petty; Ricky Rudd and Terry Labonte have since passed him. His five wins came spread across the decades, including two at Richmond.
In 1990 he crashed into Darrell Waltrip's car during Pepsi 400 practice, injuring both drivers. Waltrip missed six races; Marcis ran the event in J.D. McDuffie's car. Marcis suffered a frightening accident at Pocono in June 1999 when his car went airborne after hitting the wall head-on at high speed on the 91st lap. He climbed out uninjured.
Near the end of his career, Marcis landed the first major Internet sponsor in Winston Cup when Prodigy Internet signed on as an associate and primary sponsor between 1994 and 1996. He was a test driver for the Richard Childress GM Goodwrench No. 3 — a private arrangement with Dale Earnhardt that helped fund his own race team. After retiring from competition in early 2002, Marcis also served as a test driver for IROC and the Nextel Cup series.
Marcis became iconic for his signature look: wingtip shoes and a Goodyear hat. When he completed his record 33rd Daytona 500 start in 2002, Goodyear presented him with a special bronze trophy in the shape of those wingtip shoes. His career record of consecutive Daytona 500 starts stood as a monument to his longevity and consistency.
Dave Marcis represents an era and an archetype that no longer exists in NASCAR: the independent who could wring competitive results from underfinanced, self-built equipment through skill and stubbornness alone. His five wins, sustained top-ten presence across five decades, and near-unbroken Daytona 500 record cemented his status as one of the sport's most durable competitors.