Johnson crossed the finish line in 39th position and completed 285 laps of the 8.4-mile circuit in the modified NASCAR Cup Next Gen Chevrolet Camaro ZL1, run by Hendrick Motorsports.
The car ran as high as 27th overall but suffered a setback on Sunday morning when it suffered a driveline failure that required a lengthy repair.
“My heart is full,” said Johnson, who shared the car with Jenson Button and Mike Rockenfeller. “For all the reasons we know – coming here with NASCAR, Hendrick, Chevrolet, Goodyear.
“Many of the people here working were on different teams that I won races and championships with. There were so many familiar faces, to have this experience was just off the charts.
“The fan reception – whether it was at the parade, or on the cool down lap just now. Even the corner marshals were going nuts. Everything was just incredible.”
“My bucket is full. I’m really happy.”
The one-off entry in the centenary Le Mans event was to celebrate 75 years of NASCAR, whose president Jim France was inspired by his father, NASCAR founder Bill France Sr who brought two stock cars to Le Mans for the 1976 edition of the race.
“That was unbelievable,” said France. “That was thousands of hours of hard work by hundreds of people that went into making this thing happen. And then the way the team and the pit crews and everybody performed all week, it was just fantastic.
“I hope my dad and my brother are somewhere up there looking down and smiling, but the goal when we set out was to try and finish the race running at the end and not be last. And we accomplished that.”
Rick Hendrick, owner of Hendrick Motorsports that built and ran the car, added: “It makes me proud for our sport. The last thing I’d want to do is for us to come over here and fall on our nose. That’s what I was worried about.
“From the very beginning with Chad [Knaus, who oversaw the project] and Greg [Ives, the crew chief], I said we’ve got to do this right. We don’t spare any expense.
“Our NASCAR teams can do any kind of race they want to do. I mean, they got the talent, they've got the engineers, and they got a lot of smart people and they can do whatever.”