Martin, 43, struggled throughout the 2001 season and appeared to be near the end of a career that has seen him win 33 times on the Winston Cup circuit.
But he was fourth in the points standings coming into Saturday night's marathon race and soon moved from his 25th starting position into the top five. He stayed there all night and eventually took over the lead when Jimmie Johnson missed his pit on the final stop of the race.
Johnson dominated throughout the night, but his miscue on the pit stop left him in ninth place on the final restart and he eventually finished seventh.
Martin, meanwhile, was in first when the race resumed and he had only Kenseth to worry about.
Kinseth closed onto Martin's bumper a number of times, but never attempted to make a move past him. Over the final laps, the two leaders began to deal with lapped traffic and Martin dealt with it in a superior manner.
In addition to the regular purse, Martin won $1 million as part of a year-long NASCAR promotion.
"I'm giving most all of that money to the crew," Martin said. "I might keep just a little bit. But I can't win in a slow car and this team put me in a race car that could win.
"I don't know if I will ever win another one. I'm going to party all night and I don't even drink."
Points leader Sterling Marlin finished 11th and saw his lead over the second-place Kenseth shrink to 87 points. Martin moved into third place in the points race, 143 behind.
"This was disappointing," said Johnson, who needed a late caution to have a chance to win because of fuel problems and then got it -- only to make a mistake in the pits.
"I went through my pit stall," he said. "I knew whoever came out first or second on that restart was going to win the trophy and I made the mistake."
Robbie Gordon completed the 600 miles after running all 500 miles at the Indianapolis 500 earlier in the day. He finished eighth at Indianapolis and 16th Sunday night.
"I'm a lot tired," he said. "I got a cramp in my stomach at one time and got a cramp in my leg right at the end of the race. We were in the top five at one point in both races. I wish we could have done a little better."