Younessi began racing motorcycles at a young age before transitioning to car racing. He holds degrees in Computer Science and Electrical Engineering and went on to earn a Juris Doctor, being admitted to both the Florida and Federal Bar. He subsequently moved away from legal practice to focus on business and motorsport. In 2006 he was knighted as a Chevalier by the Order of St. John of Jerusalem, Knights Hospitaller.
His business operations include several of the highest-volume Harley-Davidson franchises in the United States, with locations in San Diego, Los Angeles and multiple Florida sites operating under names including Top Rocker, Seminole, Falcons Fury, Raging Bull, Miracle City, Mulholland, Treasure Coast and Space Coast. He also operates a Lamborghini dealership in Palm Beach.
Younessi returned to competitive car racing in 2011, entering the U.S. F2000 National Championship with Pabst Racing Services and JDC Motorsports in the series' National Class. Over seven starts he finished fourth in the National Class standings, with a best overall race result of twelfth at Road America. He also competed at Mid-Ohio that year in the F2000 Championship Series.
In 2012 he founded Younessi Racing to contest the Firestone Indy Lights series. He made two starts: the season opener at St. Petersburg, where he qualified sixteenth and finished outside the points, and the Detroit round in June, where he finished twelfth on track. He finished twenty-first in the Indy Lights points that year. He also appeared at Baltimore in the American Le Mans Series LMPC class in an Oreca FLM09.
In 2013 Younessi competed in the Blancpain Endurance Series in a McLaren MP4-12C. At the season opener at Monza, he set the fastest lap in the second qualifying session in a field of sixty cars.
Later in 2013 he drove at the 24 Hours of Le Mans with Boutsen Ginion Racing, co-driving with Thomas Dagoneau and Matt Downs. Their Oreca 03-Nissan completed 300 laps to finish 32nd overall and 11th in the LMP2 class.
Younessi has continued in GT competition into the mid-2020s. He races in GT America (SRO3 class) with Alliance Racing. In 2026 he was entered in the Porsche Supercup but did not start at Monaco.
His son Dariyan Rodin Younessi began karting at age four, continuing the family's involvement in motorsport into a second generation.
Younessi's career follows the pattern of the well-resourced gentleman driver pursuing progressively higher levels of competition: national open-wheel series, LMP2 endurance at the highest level, factory-supported GT machinery in international sprint racing, and ongoing participation in factory one-make series through the Porsche Supercup. His Le Mans start in 2013 and his Blancpain fastest-lap qualifier represent the peak of his competitive results. The breadth of championships he has entered — F2000, Indy Lights, ALMS, Blancpain, GT America, Porsche Supercup — across a span of more than a decade reflects sustained engagement with racing across multiple continents and categories.