He had several odd jobs before his racing career, including lumberjack, and most famously, New York City cab driver.

[1] Sullivan was given a 21st birthday present of a course at the Jim Russell Racing Drivers School at the Snetterton circuit in England.

In 1980–81, he drove for Garvin Brown Racing in the SCCA Can-Am Series, scoring one victory in 1981 at the season-ending Caesars Palace Grand Prix.

In 1982, he made his début in the PPG Indycar series, and was recruited by the Tyrrell Formula One team for the 1983 season at the request of primary sponsor Benetton, who wanted an American driver.

Sullivan competed in the fifteen races of the 1983 season, scoring two points with a fifth place at the Monaco Grand Prix and finishing seventeenth in the World Drivers' Championship.

Nevertheless, he was somewhat overshadowed by his more experienced teammate, Michele Alboreto (who won the 1983 Detroit Grand Prix for the team, its last F1 victory), and was not retained at the end of the season.

[2] In 1986, Sullivan was a guest star on the television show Miami Vice ("Florence Italy") playing a race car driver accused of murdering a prostitute.

Also in 1991, the Leland Corporation released the arcade game Danny Sullivan's Indy Heat, featuring his likeness.

After being released from Galles Racing very late after the 1993 season, Sullivan was unable to find a new ride as most seats at that point had already been filled.

In 1994, he had some guest starts for Alfa Romeo in the DTM and together with Thierry Boutsen and Hans-Joachim Stuck he was third overall with the Dauer 962 LM at the 24 Hours of Le Mans.

The program successfully promoted American Scott Speed from California, who drove for the Scuderia Toro Rosso team in 2006 and 2007.

[14] Sullivan and Michael Andretti were inducted into the Motorsports Walk of Fame on April 5, 2010, along the route of the Toyota Grand Prix of Long Beach, which both men have won.

[15] Sullivan serves as a senior advisor at Tempus Jets and its parent company, Orion Air Group, LLC.