Justus started his karting career in 1981 at the age of eight. In 1985 the young driver won the IKFGrand National Championship in the Junior I class. He won another Grand National Championship in 1988 in the Junior III class. In 1995 Justus started his formula racing career in the United States Auto Club sanctioned Formula Russell Championship winning the series. For 1996 Justus was one of 25 drivers selected for the Team Green Academy. After catching the eye of Atlantic Championship and CART team owner John Della Penna the plan was to replace Richie Hearn in the Atlantics race seat. However money was a factor and the budget did not come together. In 1996 Justus started four USF2000 races. His best result was in the streets of St. Petersburg where he finished fifth. Funding his racing efforts with graphics design work Justus did not race in 1997. In 1998 Justus had one single USF2000 outing, at the 1998 Colorado Grand Prix. Justus finished his Van Diemen chassis in third place for the first race, behind David Besnard and Sam Hornish, Jr.. The sole 1998 outing impressed Gerald Forsythe who brought Justus in at Cape Motorsports for the 1999 season. Justus won the third round of the season at Lowe's Motor Speedway. Later in the season Justus also won the second race at Road Atlanta. Despite missing the last four races of the season Justus finished tenth in the season standings. He returned with the team for 2000 for a full-time outing. In 2000 Justus dominated the series. Justus claimed eight pole positions in thirteen races. The young driver won five of the races and claimed the championship. After a sabbatical Justus returned for 2002 for three races in the Atlantic Championship with Performance Development & Racing. His best finish was a seventh place at the Denver street circuit. For 2003 Justus joined RuSPORT for a full-time effort alongside A. J. Allmendinger. Despite failing to win a race Justus scored four podium finishes. Justus finished fifth in the series standings. At the end of the season Justus retired from competitive autosport to run his graphics design company Manifest Group.
