Pilet began in French Formula Renault 2.0 with Graff Racing, finishing sixth in 2002, second in 2003, and winning the championship in 2004 with five wins from fourteen races. He also competed in the Formula Renault 2000 Eurocup that year, scoring a win and finishing ninth. He graduated to the Formula Renault 3.5 Series in 2005, finishing eleventh after missing three rounds, then ran a full 2006 season across GD Racing and Tech 1 Racing but ended the year twenty-first. With the single-seater path narrowing, he turned definitively to sports cars.
Pilet joined IMSA Performance and won the 2007 Porsche Carrera Cup France championship, beginning a long association with Porsche machinery. In 2008 he drove for Flying Lizard Motorsports in the American Le Mans Series GT2 class, recording five podiums. From 2009 to 2010 he raced full seasons in the International GT Open's Super GT class with IMSA Performance Matmut alongside Raymond Narac, winning five races in 2009 and four in 2010. He also shared a Porsche 997 GT3-RSR with Narac, Patrick Long, and Richard Lietz at the 2010 24 Hours of Spa, finishing second in class.
In 2011 Pilet drove for Team Art Taste in the Japanese Super GT series using a Porsche 911 GT3R, while also contesting the Le Mans Series for IMSA Performance alongside Wolf Henzler.
Pilet made his Le Mans debut in 2009, retiring. He finished fifth in class in 2010, fifth in GTE Pro in 2011, and fourth in GTE Am in 2012. His closest approach to a class win at Le Mans in GTE Pro came in 2013, when he finished second in class alongside Timo Bernhard and Jörg Bergmeister driving for Porsche AG Team Manthey. He was classified third in GTE Pro in 2019 alongside Nick Tandy and Earl Bamber. From 2020 onwards Pilet raced in LMP2 at Le Mans, with his best LMP2 result there being eleventh overall and sixth in class in 2021.
In 2020, the Porsche factory GTLM entry chose not to travel to Le Mans due to the COVID-19 pandemic. When an IDEC Sport Oreca 07 needed a replacement driver after Dwight Merriman was injured in a crash, Pilet stepped in as a reserve driver already within the mandatory pandemic bubble.
Pilet's strongest championship performances came in North American endurance racing. Driving for Porsche North America with CORE Autosport, he won the 2015 United SportsCar Championship GTLM title with four wins from ten starts. He also won the 24 Hours of Daytona in the GT class in 2014. In the IMSA SportsCar Championship he won the 12 Hours of Sebring in the GTLM class in both 2018 and 2019. With Pfaff Motorsports in 2023 he claimed a third Sebring victory in the GTD Pro class.
Pilet won the 2018 24 Hours of Nürburgring with Manthey Racing, adding Germany's most prestigious endurance event to his record of victories across three continents.
After his period as a Porsche factory frontrunner in GT racing, Pilet extended his career into prototype and GT3 competition. He contested the GT World Challenge Asia from 2023 and continued to start at Le Mans annually, finishing fifth in class in 2024 and seventh in LMP2 Pro-Am in 2025.