“High School Musical” was a slam dunk hit for Disney 20 years ago, but not for Bart Johnson — who played Coach Bolton — because he tells TMZ the movie f***** up his career at first!

It may be hard to believe, but Johnson tells us his acting career took a turn for the worse despite his skyrocketing fame as Zac Efron‘s on-screen dad and East High’s head basketball coach in ‘HSM.’

Check out our clip … Bart tells TMZ he was “put out to pasture” for being a dad in a Disney movie, and it took a whole decade to get his career back on track.

Bart also tells us ‘HSM’ had a minor impact on his personal life, claiming his kids’ elementary school barred him from dropping them off because his presence became too much of a distraction!

But Bart says he always stayed in the game and is now getting work again! In 2024, he landed the part of Aaron in Kevin Costner‘s “Yellowstone” and has a recurring role in Taylor Sheridan‘s “Landman.”

“High School Musical” debuted 2 decades ago this week and it was a game changer for Disney Channel and many of the film’s now big-name actors. As you know, Vanessa Hudgens, Ashley Tisdale and Zac all went on to do big things … proving the film was the “Start of Something New.”

During our interview, Bart also raves about how the ‘HSM’ franchise is being received by the next generation. And he teases a potential fourth installment after the third film premiered in 2008 … even telling us he pitched his own idea. It’s all in the clip.