Less than a minute into Rooster‘s pilot episode, John C. McGinley makes his grand entrance — shirtless, sweaty, and beaming with confidence. It’s his first of many revealing scenes, and though McGinley’s character Walter Mann proudly describes himself as “jacked,” when the 66-year-old actor read the script and realized he’d “be practically naked for the run of the show,” he took action.
“I hired a guy to help me shed about 44 pounds, purely out of vanity. Not out of serving the character, just as a bullheaded jackass,” McGinley told DECIDER over Zoom. “I wanted to not look like I was buckled by gravity. So I didn’t eat anything for five months. I had bone broth with truffle balls in it for the fat. And then I had about four ounces of whatever you could put in your palm every afternoon. So I don’t know about being jacked, so much as being deprived.”
When DECIDER chatted with the Rooster star ahead of Season 1’s premiere he said, “If we’re lucky enough to go back for Season 2, I’ve got to do it again.” For that reason, Rooster‘s recent Season 2 renewal was likely a bittersweet moment for McGinley. But I can’t imagine the actor being anything less than psyched to keep the HBO comedy going and embody this character who was so largely inspired by…him!
When Lawrence and co-creator Matt Tarses set out to craft Rooster‘s characters, Lawrence knew his longtime friend and creative collaborator since their Scrubs days so well that he pulled inspiration for Walt straight from McGinley’s life — right down to the hothouse!
“A couple summers ago, Billy rented a house two or three doors down from me in Southern California, and I’ve been doing the heat and ice protocol since 2001,” McGinley shared. “Billy let me introduce it to him, and we repeated it almost every other day, 15 minutes in the heat, five minutes in the ice. So he took that and integrated into the show.”

Walt is so into releasing brown fat through daily hot sauna sessions and cold plunges that he hand-made a list of Hothouse Rules in wood shop and frequently invites peers over to sweat out their troubles. In the spirit of Hothouse Rule #3, “The hothouse is for real talk,” McGinley told DECIDER which co-star is his favorite sauna scene partner. Sorry, Carell! He picked Lauren Tsai, who plays Walt’s mentee, Sunny.
“When Billy puts Sunny and Walt in the hothouse together, it’s tantamount to being in a truth barrel,” McGinley shared. “Everybody has an agenda when you walk into an environment, about what you’re predisposed to saying and not saying, but the heat is so overwhelming in the hothouse that it functions as a truth barrel. And Lauren’s character, Sunny, tells some truths that maybe she didn’t mean to, [like the one] about my beautiful necklace, that I think makes me look like Paul Mescal, even though I don’t know who it is.”
As Rooster progresses, we’ll definitely see Walt and Sunny share more deep, vulnerable scenes together — both in and out of the hothouse. McGinley is thrilled about the unlikely pairing and heavily praised his talented 28-year-old co-star.
“I love that before action, Lauren tries as an actor to get to neutral — not to a place of accomplishing an objective, but rather to zero. That’s a very hard space to occupy for actors, because we’re so objective-driven and scene demands dictate that we’re going to try to compel ourselves through the scene,” McGinley mused. “There’s 150 people pulling lights, and there’s a boom mic above us, and there’s a lot of things going on. So for Lauren to somehow arrive, not to retreat to, but arrive at zero is the stuff that admiration is made of.”

When chatting with DECIDER ahead of Rooster‘s premiere, Tsai also gushed over McGinley, saying it’s “an honor to work with the legend.”
“Even getting to walk into a set and have [his] presence there is so inspiring. I feel like there’s such a high energy, too, and [he’s] so good at motivating everyone and having this sense of like camaraderie amongst the team, which is very rare,” Tsai explained. “I feel that I’m taking a masterclass every single scene we have, because I’m getting to watch how [he] performs and how [he] prepares.”
When it comes to prepping for a role, McGinley doesn’t simply think about physical fitness. He’s also creatively connects with his characters and projects by painting.
“I have an art space, and I paint my lines and post them on the wall around the house, into my trailer. So they’re inescapable… these huge posters,” McGinley said. “It’s just a way to get the lines and the words in my body and to make them mine and not Bill and Matt’s.”
Tsai not only commended her co-star’s “extremely inspiring craftsmanship,” but told DECIDER that at the end of filming Rooster‘s first season, McGinley gifted her some of the lines he’d painted. BRB, CRYING!
So next time you see McGinley shirtless on Ludlow’s campus, hosting pals in the hothouse, or hilariously delivering lines while clothed, remember all the hard work and beautiful craftsmanship that goes into his performances.
New episodes of Rooster premiere Sundays on HBO and HBO Max.
