Catsburg had started the sole Chevrolet Corvette C8.R from pole and maintained the lead at the start before making an early stop under the safety car.
But less than 90 minutes into the race, Catsburg was back in the pits with a front-right damper failure that took nearly 10 minutes to repair and dropped Catsburg, Nico Varrone and Ben Keating two laps behind the leaders.
Yet, despite the setback, the Corvette crew battled up the order, eventually gaining a lap back with a safety car pass around before some impressive pace from the trio returned them to the lead lap.
The C8.R briefly moved back into the lead in the 17th hour, eventually winning the class by a lap.
It marked Corvette's first win at Le Mans since 2015 and brought the curtain down on the GTE Am era at the 24 Hours.
"To be honest, no - I thought this is it," said Catsburg, when asked by Autosport if he thought any fightback was possible.
"We are two laps down and the race is going to be so long and I was pissed off with that.
"I thought I was going to have to drive for so long for nothing but somehow we made it back [to the front].
"We had great pace and with the safety car the way it is now, thank god, we got a lap back and the other lap we won back by just being faster than the others. It was insane we managed to get back."
Source: Autosport