Before starting a career as a professional car racer, Danny worked as a lumberjack, janitor and Car driver and even as a waiter too in different places. Danny has gifted a course at the Jim Russell Racing Drivers School in England when he was 21 years old.
He completed his Formula Ford, Three and Two from England and returned back to the USA, where he debut in PPG Indycar series which was recruited by the Tyrrell Formula, One team. Danny builds his personality after winning the Indianapolis 500 and Michigan 500 races. The 1987 season was a big disappointment but win the CART series in 15 races. He won Long Beach and Detroit race and tries to make a CART comeback but didn’t come. Sullivan ended the season with a huge crash at Michigan which left him with a broken pelvis and with that his racing career came to end.
In 1996 he got married to his girlfriend Brenda Bosveld with whom he has been dating for several years. It has been estimated that Danny has the Net worth of U.S $ 50 Million.