Pat Rooney has reached that enviable state in life in which one can do pretty much as he pleases. Even more happily, what he wants to do has worth. And, perhaps best of all, he's very good at what he does.

Rooney is the beloved and benevolent commander in chief of ball boys and girls at major tennis tournaments in New York City, and for more than 30 years his minions, who invariably address him as Mr. Rooney, have scurried across the courts at the U.S. Open, scooping up loose balls like obsequious shortstops. Rooney also recruits, trains and deploys ball chasers for the Volvo Masters and the Virginia Slims championship. At Fordham, the Jesuit university and secondary school in the Bronx, where he coaches the women's college and boys' prep teams, one can sometimes spot him in his rakish Irish woolen cap on the porch of the hallowed red brick tennis house, calling foot faults in matches three courts away.

In his wonderfully rambling apartment a quarter of a mile from Fordham, Rooney is surrounded by books, sepia photographs of his family and picture postcards from former protégés. He's a cheerful, tweedy bachelor who wears steel-rimmed spectacles and, in his lapel, a duck-shaped pin that says QUACK. Quack is a Rooneyism that can mean just about anything. "It always livens things up," he says. He'll caper through a maze of anecdotes, insights and opinions. His trademark tag line is, "Do you follow me?" Yeah, sometimes.

Rooney is a gentleman of exquisite sensibility, ever courtly on and off the courts. "The flowers outside the fence belong to the Jesuits," he once told one of his women players, "but inside they belong to Rooney, who'll dispose of them in an appropriate manner." And with that he plucked a rose and bestowed it on her.

Although Rooney is reticent about divulging his age, he concedes that the 150 people who threw him an "80th birthday" party last August were in the right vicinity. "Let's just say I can buy a cocktail without having to pull out my draft card," he says. As far back as six decades ago Fordham's yearbook, the Maroon, described Rooney, then a senior at the school, as "an authority on the little niceties of life."

Rooney's beginnings in tennis go back to 1919, when he was a teenager living on Manhattan's West Side. "There was a girl," he says. "Claire Sullivan. I'd taken sort of a shine to her." One day her father invited Rooney to a family outing in Yonkers. "We're going to play tennis," said the elder Sullivan.

"," muttered Rooney. He was a New York Giants fan, and only baseball mattered. But he went along because Claire was going.

By the day's end, it seemed Rooney was more smitten by the game than by the girl. It was tennis that led him to enroll at Fordham University a few months later. "In those days," he says, "the school had 12 delicious courts. I thought. 'Oh boy, this is for me.' It's the reason. It's the truth. Do you follow me?"

Rooney made the varsity his sophomore year and never lost an intercollegiate doubles match—or ever took a formal lesson, either. Instead, he patterned his game after some of the popular players of the day: Ingo Hartman's forehand and Bill Tilden's backhand were two of his models. "Big Bill could make the ball almost talk," he says. "A few times I even heard it whisper."

Graduating from Fordham in 1924 with a degree in philosophy, Rooney went to work in the oil fields of Oklahoma as a surveyor and later on Wall Street, where he sold bonds. During World War II he served as a lieutenant commander in the Navy. By the late '40s he was back at his alma mater doing graduate work in physics. After receiving an M.S. in 1946, Rooney began teaching math at Fordham Prep, and he introduced tennis there in 1949. He has been coaching the Rams ever since—and has 15 New York City Catholic league titles to show for it.

Ten years ago Rooney was more or less drafted to coach the first women's team at Fordham. He accepted any aspirant who could hold a racket. Since that maiden 2-3 campaign, the Lady Rams have been 172-24 against the likes of Vassar and Barnard.

Rooney is so inconspicuous a coach that he's practically invisible. If something works, he won't tinker with it. "I believe in coaching minimally," he says. "I'm a tremendous believer in a relaxed attitude in sports. I like people to work things out themselves. And I never yell. It's totally destructive. Do you follow me?

"I like my girls to get off the courts in an hour and a half. That way they can have dinner at a reasonable hour and still have time to crack a book at night." This emphasis on academics may account for his squad's collective 3.5 grade point average.

Having supervised the ball kids at the Open since the mid-'50s, Rooney was the logical man for the Virginia Slims people to turn to in the early 70s to assemble a crack cadre of ball girls. "The girls' aim didn't always match their enthusiasm," Rooney recalls with some chagrin. "They tended to throw the balls into the stands. Do you follow me?" He has trained the ball boys and girls for Madison Square Garden tournaments for 20 years.

To fill out the corps of 160 ball chasers for this year's Open, Rooney held tryouts for candidates from all over the country. They ranged in age from 16 to 28 and had to impress Rooney with their speed, agility and common sense. "For heaven's sake!" he says. "If they don't have any common sense, they'll ruin us." The ideal ball girl or boy is unobtrusive. Over the years a few "wise-guy kids" have become too visible, but Rooney is far too tactful to name any of them.

John McEnroe, he says, was a model ball boy. Rooney watched him hound balls for three years at Forest Hills. "I never had a moment's problem with Johnny," he says. McEnroe remembers Rooney lacing his sideline commentary with Latin phrases. "Res ipsa loquitur," Rooney might say after a service ace. That is, the thing speaks for itself, or "Enough said."

Mr. Rooney's quirky speech brought a mild rebuke from Fordham's new president this summer. "I just met you," said the Rev. Joseph A. O'Hare, "and all you want to know is whether I follow you."

It's all subconscious, Rooney insists. "I guess I want to make sure that I have people's attention," he says. "Do you follow me?"

Then, catching himself, he says, "There I go again."

PHOTOMANNY MILLANMr. Rooney and his ball kids hold court at Flushing Meadow.