Gavin first burst onto the Broadway scene in 2002 playing Jimmy Smith in Thoroughly Modern Millie, opposite fellow rising star Sutton Foster. The role earned him his first Tony nomination, Best Leading Actor in a Musical. He received his second nomination, in the same category, for Hair in 2009. He finally won a Tony for Best Featured Actor in a Musical in 2017 for his work in Hello Dolly!. He dedicated the award to the University of Michigan’s musical-theater department, his alma mater.

In 2023, Creel performed an autobiographical show, Walk on Through, about falling in love with the Metropolitan Museum of Art, billing himself as a museum novice who learned to love art. In it, he worked through his relationships with men, with religion, and with art. “I had a really hard time during the writing of it, during my life during the pandemic, losing everything that I thought gave me my identity,” the actor told TheaterMania in 2023. “And I said, ‘I’m gonna write this piece to try to heal and let go and find a way forward,’ and I think I’m on that path. I’m finally owning it, and it’s terrifying to put it on stage, and yet, this is the theater that I want to make, if I’m lucky enough to get to create more.”