Who Is Mark Kerr? Meet the MMA Fighter Who Inspired 'The Smashing Machine'

Dwayne “The Rock” Johnson completely transformed into fighter Mark Kerr for the biographical sports drama The Smashing Machine. Johnson committed to the role so much, he sat in the makeup chair for several hours each day to apply over a dozen prosthetics to his face. “I just sat in front of that mirror for three to four hours and watched it all change. There were about 13 or 14 different prosthetics. Subtle, yet I think very impactful,” Johnson told Vanity Fair of the transformation in August 2025. But for the WWE superstar, portraying Kerr wasn’t just about looking the part, it was a matter o