Huff was born on Christmas Day 1979 in Cambridge and attended St Faith's School and The Leys School from 1993 to 1996. He came through karting before winning the 2000 Formula Vauxhall championship and finishing as class runner-up in the 2001 Ethyl MG Championship. His breakthrough came in 2003 when he won the inaugural SEAT Cupra Challenge, earning a paid BTCC drive alongside former champion Jason Plato for the following season.
Huff made his BTCC debut in 2004 with the SEAT squad run by Ray Mallock. He claimed his first race win at Brands Hatch and a second at Snetterton, finishing seventh overall in his debut campaign. After departing for the WTCC, he made occasional returns to the BTCC: a guest appearance with PMR at Silverstone in 2017, where he led for much of race three before finishing second, and a one-off outing with Team HARD at Knockhill in 2023.
Huff returned to the BTCC full-time in 2024, driving a Toyota Corolla for Speedworks Motorsport. He won the reverse-grid race at Snetterton and later at Knockhill. The Snetterton victory established a new record for the longest gap between BTCC race wins at nearly twenty years, surpassing the previous record held by Dennis Leech by two years.
When Ray Mallock's company took on Chevrolet's nascent WTCC programme, Huff was retained as a driver. His debut 2005 season with the Lacetti was difficult but he scored the car's first championship points with a sixth place in Mexico. In 2006 he took Chevrolet's first dry-weather WTCC win at Brno, having started from 24th on the grid after penalties and fighting through to lead race two.
Progress continued in 2007, with a win at the Scandinavian Raceway and three additional podiums. The team's strongest individual results came across the later Cruze era. In 2008 Huff finished third in the championship behind SEAT drivers Yvan Muller and Gabriele Tarquini. In 2009 he won at Morocco, taking the first victory for the Chevrolet Cruze, and also triumphed in France, finishing the year fifth overall.
The 2011 season saw Chevrolet dominate and Huff contest a tight intra-team title battle with Muller. Huff led the standings early in the year and won both races at the Macau finale, but Muller secured his third WTCC title by race's end.
The 2012 championship, Chevrolet's announced final WTCC season, produced one of the more dramatic title conclusions in the series' history. Muller led for most of the year, but a collision with team-mate Alain Menu in Shanghai allowed Huff to take the race win and a decisive points swing. Going into the Macau finale with a 37-point lead, Huff made contact with the barriers in race one while leading and was forced to retire. Chevrolet mechanics repaired the car for race two — including contributions from Menu's and Muller's crews — and Huff started eighth, needing fifth to secure the title. He finished second behind Menu, which was more than sufficient. The result gave Huff the 2012 WTCC championship, the first WTCC title for a British driver in five years, and ended Chevrolet's programme with a 1-2-3 team finish.
Huff joined ALL-INKL.COM Münnich Motorsport for 2013 in a SEAT León WTCC, then moved to Lada Sport for a two-year deal from 2014 through 2015. Driving the Lada Granta in 2014, he scored two race wins, his results standing out given the car's lack of manufacturer parity compared to the dominant Citroën. Lada introduced the new Vesta for 2015, developed with assistance from the French company Oreca.
From 2016, Huff raced for Honda as a factory driver alongside Tiago Monteiro and Norbert Michelisz, winning at Suzuka's home race and finishing fourth in the standings. In 2017 he was again among the title contenders but the championship went to Thed Björk at the final round in Qatar.
After the WTCC merged with the TCR International Series to form the World Touring Car Cup (WTCR) in 2018, Huff continued competing at the top level. He also won the 2020 Scandinavian Touring Car Championship title, adding a second national touring car championship to complement his 2012 world title.
Huff's 2012 WTCC championship came in circumstances that required patience, consistency, and a remarkable last-race recovery, having returned from what appeared to be a terminal points deficit in the Macau finale. His career spans nearly three decades of professional touring car racing across the BTCC, WTCC, and TCR-era competition, with top-level wins across multiple championships and manufacturers.