Sugden began in karting and became British champion before moving into single-seater racing. He won the Star of Mallory series in Formula Ford 1600 in 1987, driving the works Swift "Tredaire" car for Frank Bradley. He also competed in the Honda CRX Challenge and British Formula 3000, and in 1990 finished third in the Formula Renault Championship, claiming one race victory.
Sugden made his British Touring Car Championship debut in 1990, entering selected rounds with the Prodrive-run Junior BMW Team in the 2.0-litre class. An impressive 1991 campaign — including a win at Brands Hatch — earned him tenth place overall despite contesting only five rounds. That form secured a full season in 1992 with the works BMW team, where he ended the year eighth in the standings.
When Prodrive's BMW contract concluded, Sugden remained with the outfit for an abortive Mercedes programme in 1993 before returning to the BTCC in 1994 as a third driver for the Toyota works team alongside 1991 champion Will Hoy and former Formula 1 driver Julian Bailey, the trio driving the Toyota Carina. He was elevated to a full-time seat in 1995 but the team were not front runners and neither season yielded the results his talent suggested. 1995 proved to be both Toyota's and Sugden's final year in the BTCC. He remained active in the paddock in 1996 as a test driver for Vauxhall as they developed the Vectra, while concurrently contesting the Volkswagen Ventro VR6 Challenge and finishing third.
Sugden pivoted to sports car racing in 1997, entering the British GT Championship and winning the GT2 title outright in his debut season, sharing a Porsche 911 GT2 with Steve O'Rourke. He then captured the GT1 title in both 1998 and 1999, first in a McLaren F1 GTR and then in a Lister Storm GTL — consecutive class championships across two different machinery programmes.
His international debut came at the 24 Hours of Le Mans, where he finished fourth overall in 1998 driving an EMKA McLaren. That result opened the door to full-time FIA GT Championship competition from 2000 onwards, a series in which he accumulated nine wins and finished runner-up in the GT2 class in 2005. That same year he claimed the Porsche Cup, awarded by Porsche to the leading privately entered Porsche driver across its major international championship programmes — only the second British driver to win the accolade.
Sugden extended his sportscar résumé with appearances in the American Le Mans Series, finishing second in class at both the Sebring 12 Hours and Daytona 24 Hours, and competing in the Le Mans Series. He returned to the British GT Championship periodically and in 2011 finished second in GT at the Daytona 24 Hours driving a Porsche for Paul Miller Racing.
In Asia, he won the Porsche Carrera Cup championship outright in 2007, followed by third in 2008 and second — by a single point — in 2009, demonstrating a consistent presence among the leading Porsche privateers worldwide.
Away from circuit racing, Sugden made an unexpected debut in BriSCA Formula 2 Stock Cars at Skegness Stadium on 9 October 2010, winning his very first Final despite having worked at Brands Hatch earlier that day. He received an immediate upgrade to Yellow Top status. He continued in selected F2 rounds, winning the Grand National Final at Birmingham in November 2010, and in early 2011 added the Grand National Final at Northampton and an outright Final victory at Birmingham, earning promotion to Blue Top. The crossover highlighted the breadth of his driving ability across fundamentally different forms of motorsport.
Sugden's career is distinguished by his versatility — British Touring Car Championship race winner, multiple British and international GT champion, Le Mans front-runner, Porsche Cup laureate, and stock car champion — combined with his parallel identity as a team owner and businessman. Few British privateer drivers of his era matched the range of competitive successes he achieved across so many different series and car types.