The driver for Target/Chip Ganassi Racing nipped Al Unser Jr. at the start/finish line by just a few inches to win the Boomtown 500 at Texas Motor Speedway.
The .0111-second margin of victory is the closest finish in Indy car history.
It was the only lap that Ward led as the nose of his car was less than a foot ahead of Unser's car, thrilling a crowd of 83,476.
"That was great," Ward said. "We hung in there and the Target guys did a fantastic job. I have to thank Chip Ganassi for giving me this opportunity. We knew we had to make that last pit stop a good one. We were in and out and we did it.
"Thank God for this one. This is a turnaround. Now, we can look forward. I've waited a long time for this victory. Fifty-one career starts and now I'm a winner."
Airton Dare was third, followed by two-time Indy 500 winner Helio Castroneves and Felipe Giaffone.
"The crew did their job, the car did it's job, but Ward had the draft on me and that's what won it for him," Unser said. "I could have done some bad stuff on the back straightaway, but that's just not worth it. I ran it on the bottom and thought we had enough but at the end, it wasn't enough.
"Jeff Ward did a great job and he earned it for sure."
Tomas Scheckter dominated the race, leading 108 of the first 160 laps before he dropped out of the race with clutch failure on lap 160 following what would have been his final pit stop.
It was another heartbreaking finish for the 21-year-old rookie from Capetown, South Africa, who also led 85 laps in the Indianapolis 500 before crashing in the Turn 4 wall 27 laps from an apparent victory.
"I put it in neutral and when I tried to pull out, the car just wouldn't go,"