Don't wish actor Jim Dale the traditional "Break a leg." In his last hit, he cracked a rib in three places and fractured his heel. Now, as the star of Barnum on Broadway, Dale has a chance to ruin himself good. He is catapulted into the spotlights by a trampoline early in the first act and later walks the length of the St. James Theater stage on a tightwire. "The nights old P.T. is not very pleased," Dale says, "he kicks the rope from under me." Jim falls about once a week and even toppled twice one evening. No matter. His showmanship could not be more surefooted, and last week the 44-year-old British actor won a Tony for best performance in a musical.

Barnum has meant the recognition Dale has sought since he left home at 16 to join a vaudeville troupe. Along the way he has been a magician, comedian and songwriter. His lyrics for the title song of the 1966 movie Georgy Girl won him an Oscar nomination.

Known as a quick study, Dale learned many of his Barnum routines at a Manhattan circus school the month before the show opened in May. His breath-takingly energetic performance has left him 16 pounds lighter, but so far he has escaped with minor bruises. He wasn't so fortunate in Scapino, a musical version of a Molière farce. Cast as a scamp, he injured the rib doing a somersault and the heel when he failed to catch a swinging rope. Yet he never missed a performance. "I'm not a fatalist," Dale says. "I don't think of dying, but of living. I wasn't born for millions of years and it didn't bother me at all."

Where he was born did depress him. His hometown of Rothwell, 170 miles north of London, had 17 factories, 17 pubs and no movie theaters. "I had a dream when I was 9," he says, "a dream about hearing laughter." Dale's father, William Smith, worked in a foundry and his mother, Miriam, in a shoe factory. Jim changed his surname in 1954 because there were two other British comics named Jim Smith. "I kept receiving their notices—which were better than mine," he jokes. Dale's younger brother, Michael, now 36, became a welder. "I don't know what made me so different," the actor says. His visits home were disconcerting at first: "I wanted to talk about my ambitions and dreams. They wanted to talk about Mrs. Wilson's cat having kittens."

By the time he was 21, Dale found himself a pop singing star, thanks to an appearance on a TV rock show. After that he was able to manage a respectable income for his wife, Patricia Gardiner, a nurse, and a growing family. They eventually had four children (Belinda, now 23, Murray, 20, Adam, 17, and Toby, 14). Dale later became a disc jockey, TV talk show host and movie actor. In 1969, at the invitation of Laurence Olivier, he joined Britain's National Theatre, and in 1974 he made his first U.S. appearance with the group in The Taming of the Shrew. Two months later he opened on Broadway in Scapino.

Since then Dale has acted in three Walt Disney films (Pete's Dragon, Hot Lead and Cold Feet and Unidentified Flying Oddball). He and his wife separated in 1977, and the following year Jim left London for Manhattan. Though not yet divorced, Dale has a new love, Julie Schafler, 32, owner of an expensive Manhattan boutique. They live in separate apartments but share midnight dinners. "During curtain calls I am always thinking, 'I'll be with Julie in 20 minutes,' " Dale says. In spare moments they shop for antiques or puppets and clowns for Jim's collection.

Dale envisions a future doing films "for bread" and theater "for love." After his one-year contract with Barnum expires, he hopes to find another play that "allows me to give people something more exciting than this humdrum existence. I want to show them a rainbow."