The two married in 1996. Afterward, they went on to make chart-topping duets and break records with the highest-grossing country music tour of all time. But McGraw said their greatest hits are their three daughters Gracie, Maggie and Audrey.
Together, McGraw and Hill have stood against the pressures and tabloid scrutiny of a dual-celebrity marriage living in the spotlight.
"She's definitely put up with a lot from me," McGraw said. "There was a point in my career here ... where … I was letting too much of me be the focus. And she sort of ... put up with me through sort of that mess a little bit."
It wasn't the first time McGraw has had a hard time of it. As a small-town boy in Start, La., he remembers seeing his mother struggle.
"I saw a lot of abuse that my mother took from two different marriages," McGraw said. "So, I think, growing up, and as I got older and all through my life, I've always looked at examples of what not to do and what not to be. [Abuse] never crossed my mind."
McGraw is famous for defending women. In fact, he's become a YouTube sensation for tossing concert-goers out of his show when he believes that they're mistreating women.
It's an opportunity to set a good example for his own family, he said.
"I just don't want my girls to think that that's appropriate. I don't want them to think that that's ever the right thing to do," he said. "And they should never accept that ... from anybody."
Perhaps McGraw's biggest emotional challenge was a secret his mother hid from him throughout his childhood. His mother, Betty, had a brief romance with one of major league's most famous pitchers, Tug McGraw.
Even though the pitcher was really McGraw's father, he grew up believing that his mother's husband, Horace Smith, was his biological father.
At 11, he finally learned the truth. But his early relationship with Tug McGraw was rocky, and there were times when his major league pitcher father didn't want anything to do with him.
He said he internalized his feelings of frustration.
"I probably did more damage to myself over those kind of feelings than I did with anybody else," McGraw said. "But probably the main reason it turned out better than it could have, it's because of the strength of my mother and the strength of my grandmother, and the love that I felt from them."
Despite the tense relationship between father and son, he said the pitcher's life was a source of inspiration.
"It changed who I thought I could be, and what I thought I could do with my life. I owe a lot to him because of that," McGraw said. "No matter what kind of father he was or wasn't for me. I got something that I ... couldn't have gotten anywhere else."
As he grew into a young man, the resemblance to his father was uncanny. Finally, Tug McGraw no longer denied his son. The two grew closer, becoming a part of each other's lives. And Tim eventually took the last name "McGraw."
"I never looked at it as forgiveness or not forgiveness, he said. "I looked at it as, it's your life. These are the hands, the cards that you're dealt."
Later, Tug McGraw battled brain cancer and died in 2004. He chose to live his final days at a cottage on Tim McGraw's Bear Creek farm.
McGraw channeled his experience with his father into his iconic hit, "Live Like You Were Dying," an anthem of forgiveness, inspiration and joy.
He closes almost every show with the song, which has become his personal prayer.
"I only have one life and I want to be happy with how I've lived it. Every day I try to make a step in the right direction," McGraw said.