The Dutch striker suffered a career threatening knee injury when he was with PSV Eindhoven and invited the surgeon, who operated on him, to the game against Club America in Los Angeles on Sunday.
Van Nistelrooy scored Manchester United's first goal in a 3-1 victory over the Mexican team.
"I was very happy to invite him here today with his grandchildren and nephews. I was happy to score because he was there too. It was a good day," he said.
"I wanted to show him that I am fit and I saw him after the game in the dressing room and I just thanked him so much. I can't stop thanking him for doing such a great job for me and getting my career back on track," the striker added.
Steadman has operated on many famous sports stars.
Among the most recent patients at his prestigious Steadman Hawkins clinic in Vail, Colorado was Los Angeles Lakers basketball star Kobe Bryant.
"When you have an injury like that you hope that you can play one day and don't think how good you can become," Van Nistelrooy said.
"The only thing I thought was I want to play at it doesn't matter at what level. I want to be able to play football again, I want to be able to walk normal again, those things go through your mind."
