Even at 24, Casella is an elfin 5'5" and looks as if puberty is not yet finished with him. These days, though, he feels lucky to be able to pass as a kid. Cast as the hormone-addled teen Vinnie Delpino on Doogie Howser, M.D., the ABC series about a boy genius working as a doctor in a Los Angeles hospital, Casella plays Norton to star Neal Patrick Harris's Ralph. In the hit show's third season, Casella's role has become even larger: For two episodes, Doogie and Vinnie even shared an apartment.
Freed from parental rules, the twosome turned to that traditional teenage obsession—sex. In the Sept. 25 season opener, Doogie lost his virginity. But Vinnie isn't so lucky: The show's producers have decreed that he will remain a virgin indefinitely. "I guess a horny Vinnie is a funny Vinnie," Casella says.
Smoking a cigarette in the living room of his one-bedroom Hollywood apartment, Casella adopts a grownup air. He has decorated his walls with Frank Sinatra posters (on the Doogie set, Casella sometimes will break into one of 01' Blue Eyes's standards) and crammed his bookshelves with Sherlock Holmes memorabilia (he hated reading until he discovered the sleuth stories at age 19). "Vinnie is not as angry as I was when I was his age," he says. "There was anger about looking so young and not being able to do the girl thing when other guys were doing it."
Even before girls entered the picture, Casella felt the pain of being an outsider growing up in Cambridge, Mass. His father, David Deitch, a former Boston Globe columnist, and mother, Doris Casella, a social worker, separated when he was 10. "For a while I'd spend one week with one and the next with the other," Max says. "I really hated that." When the divorce was finalized three years later, Max, who was living with his mother, adopted her surname. (His brother, Lorenzo, then 17, was already living on his own; also 5'3", Lorenzo is now a photographer in New York City.)
Casella's talents as a young artist helped him overcome some of the stigma of being short and inept at sports. "Kids would be awed by my drawings," he says. But at age 12, he found an even better way to impress his sixth-grade peers when the director of a high school production of Pippin recruited him for the role of the pint-size character, Theo. Casella quickly developed a passion for acting and began working in various amateur-theater productions in the Boston area.
After graduating from Cambridge Rindge and Latin High School in 1985, Casella moved with his mother to her hometown, New York City, and enrolled in professional acting classes. To cover his expenses, he swept the floors and worked in the box office at an off-off-off-Broadway theater run by veteran character actor Sid Armus (Postcards from the Edge), who helped him get small TV roles in episodes of Kate & Allie and The Equalizer. Casella landed the part of Vinnie in 1989, after his first audition.
Leaving his mother and moving to Hollywood was tough. "Oh, my God, it was the worst!" Casella exclaims. "I'd never driven before, and I didn't know anybody. I'd come home from work every night, and it'd be like, argh!" For the past year, he says, a steady girlfriend has helped him cope with the homesickness. In un-Vinnie-like fashion, Casella refuses to divulge his girlfriend's name because, he says, "she is very shy." Yet, sounding more like his cheerfully hyperbolizing alter ego, he cannot resist proclaiming that she works at the Los Angeles Zoo taking care of the gorillas. "When they see her coming, they go nuts," he says. "It's like Gorillas in the Mist."
During Doogie's summer hiatus, Casella worked on the Disney musical Newsies, due out next year. In the movie, which is based on the story of a turn-of-the-century newsboy strike in New York City, Casella is cast once again in a supporting role as an adolescent. "Nobody is asking me to play older, because I don't look older," he says. "I don't mind. I want to work." There are times, though, when Casella wishes the people around him would act more grownup. One day, he claims, his girlfriend visited him on the Newsies set, and he was appalled by the reaction of some of the teenagers in the cast. "Guys would come up to me and go, 'Oooh, she's got big ones! What's it feel like to do it?' " he says. "I was like that too once, but now I'm like, 'Get a Playboy and go enjoy yourself! Leave me alone!' "
CRAIG TOMASHOFF in Los Angeles