Button made his endurance racing debut at the 1999 24 Hours of Spa with BMW Team Raffanelli. Sharing a BMW 320i E46 with David Saelens and Tomáš Enge in the SP class, the trio retired after 22 laps with a fuel tank failure. He began discussions with SMP Racing about sharing a BR Engineering BR1 car in the Le Mans Prototype 1 (LMP1) class with Vitaly Petrov and Mikhail Aleshin in April 2018. Button and SMP Racing concluded with an agreement for him to drive most of the 2018–19 FIA World Endurance Championship. Making his FIA World Endurance Championship debut at the 2018 24 Hours of Le Mans, electronic problems dropped the car down the order before the team retired with an engine failure late in the race with Button driving at the time. He finished fourth at the 6 Hours of Fuji and was third at the following 6 Hours of Shanghai. Button missed the 1000 Miles of Sebring and 6 Hours of Spa-Francorchamps because of Super GT commitments, and the 2019 24 Hours of Le Mans because his fiancée was due to give birth to their first child.