When Jeremy Jordan played a young, naïve cop in the Broadway show “American Son” alongside Kerry Washington, in 2018, he was fresh off several seasons on the “Supergirl” series. And so he tried to apply some of the techniques that worked for him on TV to a taut drama about police violence.

“I had been making it work for so long, trying to mine gold from every moment, and I think that had stuck with me,” Jordan said. The director Kenny Leon intervened, with advice that Jordan still carries with him. Literally.

“He gave me this note on some old piece of script,” Jordan said, fishing a tiny scrap of paper from his wallet and carefully unfolding it. “It says ‘you are good enough to just say these words.’”

Leon’s counsel may be evergreen, but it particularly resonates with Jordan’s new project, where he is often unable to use many physical acting techniques.

In “Floyd Collins,” which is at the Vivian Beaumont Theater, Jordan portrays the title character of Adam Guettel and Tina Landau’s musical, a hardscrabble Kentuckian who becomes trapped while exploring a cave in 1925. As a media circus forms on the surface, Floyd withers away underground, stuck between rocks. (The musical is based on a true story, which also inspired the Billy Wilder film “Ace in the Hole,” from 1951.)