The Baltimore-born actor, starring in the national touring production of the perennially popular musical "Mamma Mia" that hits the Hippodrome this weekend, first revealed the tendency during his early years growing up in Woodlawn.
"My brother used to write plays that I performed in the backyard," said DeBoy, 56. "They were basically rip-offs of 'The Dick Van Dyke Show.' We did them during muscular dystrophy [fundraising] carnivals and charged people a nickel."
DeBoy kept at it. So did his brother — David DeBoy is an actor (and creator of the immortal "Crabs for Christmas" song). A cousin, also named Paul DeBoy, got into the profession, too, initially billed as PJ DeBoy.
"I guess there is some theatricality in the family," said DeBoy, who has another cousin in a field at least partially related to theater — politics. That would be Steven J. DeBoy Sr., a state delegate from District 12 in Baltimore County.
While still in high school, Paul DeBoy spotted a magazine ad for the American Academy of Dramatic Arts in New York with pictures of its famed alumni. He went to study there, as well as London's Royal Academy, but ended up back in his hometown for the first phase of his career, enjoying gigs at the Bolton Hill Dinner Theater and other local places.
He met his first wife in the process and relocated to Baltimore for several years. When the marriage went south, he headed back north. He has lived in New York since 1992.
Much of DeBoy's acting career, though, has been in regional theater across the country. He's a particular favorite at the Repertory Theatre of St. Louis, where a director encouraged DeBoy to audition for the latest "Mamma Mia" touring cast.
"They found out I could sing, so I they gave me the part of Harry," he said.
Harry is one of three men invited to a wedding in Greece. The bride-to-be's mother, Donna, dated those men years earlier; one is the girl's father.
"Harry's a great character," DeBoy said. "He's British and a banker; you can't get more staid than that. He's lost something in his life, and he's looking for the spontaneity he had when he was a much younger man."
The kicker is that Harry's fling with Donna was experimental; he turned out to be gay.
"That gay issue was a much bigger shock in 1999 when the musical opened in London," DeBoy said. "It gets a nice reaction now."
The plot of "Mamma Mia" is propelled by songs of the Swedish pop group ABBA.
"I wasn't ever a fan of their music," DeBoy said, "but I knew it. How could you not, growing up in the '70s? I've come to really appreciate the genius of it. The only thing is that I'm a baritone, and a lot of the music is pretty high for me. But I've gotten used to it."
"Mamma Mia" is still running in London after 13 years, and on Broadway after 11. The national tour started in 2002 and wraps up in August.
"It's not an old, tired show," said DeBoy, who joined the touring company in 2010. "The drive is still there."
Although the actor has worked in Maryland in recent years, including an appearance — in the altogether — in the John Waters film "A Dirty Shame," this will be his first performance at the Hippodrome. He's expecting "a ton of family" and high school buddies to be there.
"I'm going to Faidley's at Lexington Market for a crab cake, I know that, and to Fells Point, my favorite place in Baltimore," DeBoy said. "I only wish I could see the Orioles, too, but they're not in town. They're doing so great this year. When the show is in Cleveland in July, they'll be there, and I plan to take a personal day to see my hometown team play."
If you go
"Mamma Mia" will be performed at 8 p.m. Friday, 2 and 8 p.m. Saturday, 1 and 6:30 p.m. Sunday at the Hippodrome Theatre, 12 N. Eutaw St. Tickets are $30 to $75. Call 410-547-7328 or go to ticketmaster.com.