Born on 19 January 1985, Guerrieri graduated through Formula Renault 2000 championships from 2001 to 2003, winning the Formula Renault 2000 Masters series in 2003 with three victories. His performance secured a step up to International Formula 3000 for 2004 with BCN Competición. In that debut year he finished seventh overall, tied on 28 points with compatriot José María López, with his best result a third-place finish at Hockenheim.
When Formula 3000 converted into the GP2 Series for 2005, Guerrieri was unable to secure a drive in the new championship. The transition created a narrow window, and the Argentine — despite his competitive showing in F3000 — found himself without a seat when the grid was finalised. This outcome redirected him to the Formula 3 Euro Series for 2005 and 2006 with Manor Motorsport.
Guerrieri spent two full seasons in the Formula 3 Euro Series. In the 2006 season he finished fourth in the standings with 58 points, recording two wins and two pole positions — a competitive result in a series that served as a parallel ladder to GP2 for many European-based drivers of the period.
Following his Formula Three stint, Guerrieri contested British Formula 3 in 2007 and 2008, the second year producing a second-place finish at Monza. He then moved to Formula Renault 3.5, taking his first win in that category in the final race of the 2008 season. In 2009 he competed in Superleague Formula, winning two races.
His persistence with single-seaters eventually led to the United States. For 2011 he moved to Indy Lights with Sam Schmidt Motorsports, finishing runner-up to teammate Josef Newgarden with three wins. He repeated second place in 2012 behind Tristan Vautier, again claiming three wins including the Indianapolis 500 support race. Despite two consecutive Indy Lights runner-up finishes, budget constraints prevented the IndyCar promotion he had pursued.
After returning to Argentina for 2013 and competing in Turismo Carretera and Super TC 2000, Guerrieri found his most successful arena in World Touring Cars. He joined the World Touring Car Championship in 2016 with Campos Racing and signed for the Honda factory program in 2017. Across the WTCR era from 2018 to 2022, he accumulated ten race victories — more than any other driver in the series — finishing championship runner-up in 2019. He won the Nürburgring 24 Hours in the TCR class in 2020.
Guerrieri's inability to access GP2 in 2005 — despite strong F3000 form — illustrated how competitive and under-resourced the transition was for drivers outside established European factory academies. His subsequent career across multiple continents and categories, culminating in the WTCR's all-time wins record, demonstrated that the GP2 route was never the only path for a driver of his calibre. His Formula Renault Eurocup championship in 2003 remained his most prominent single-seater title, but his legacy is defined primarily by his touring car record.