Mike Buckley knew at an early age that he wanted to be a doctor. He was fascinated by the family pediatrician's ability to figure out what was ailing people. His father, whose ambition to be a doctor was interrupted by World War II, worked at what was then Smith Kline & French supervising clinical research budgets. Doctors were always coming by the house, talking about the excitement of their jobs.

After Malvern Prep, where he blossomed as a swimmer, Buckley went to Yale University, where he continued to excel in the breaststroke, gaining all-America status. At the 1968 NCAA championships, he won a silver medal, missing gold by 1/100th of a second.

In the classroom, he majored in English. Although a heavy load of science was required for aspiring physicians, he knew he'd be miserable. Besides, studying English would teach him how to express himself, on paper and in speech, and the great books are primers about how to lead a good life.

Fulfilling and meaningful work, a loving family and friends, the esteem of professional colleagues - by those measures and more, Buckley's life has been good. Now, a new chapter is beginning with his retirement as executive director of Pennsylvania Hospital, an institution he has served for 37 years.

After medical school at Yale, Buckley did his residency at the University of North Carolina, Chapel Hill. There, he found his specialty - infectious disease - and he continued training at the University of Pennsylvania. Preferring clinical practice to research, he moved to Pennsylvania Hospital in 1977.

"I liked being a specialist," Buckley says. "Infectious disease employs plenty of cognitive skill. There's a lot of detective work as you explore the history and pattern of an illness. Plus, you get a lot of people better. I'd do it over in a second."

As AIDS became the scourge of the city's gay population, Buckley and his medical partner, Stephen Gluckman, soon developed one of the largest AIDS practices in town. They were at the forefront in investigating treatments and medications that would alleviate the lethal collateral damage of the disease.

In time, Buckley assumed leadership roles at the venerable hospital - chief of infectious disease, associate dean, chairman of the department of medicine, and finally, executive director, or head of the entire hospital. As his administrative responsibilities grew, he still tried to find time for his principal professional pleasures - seeing patients and teaching young doctors.

"It was never hard for me to come to work. I love being a doctor. It's intellectually stimulating and rewarding, and you feel you're doing direct good for people. The relationships with different kinds of patients were always the most interesting part of medicine to me, talking to them and finding out about their lives."

When Buckley was in college, his father told him, "If you want to be a doctor, don't go into it for the money."

"He was absolutely right," Buckley says. "Infectious disease is at the low end of the financial totem pole, and if you go into it to make a lot of money, you'll be disappointed."

Buckley enjoys reading "The Corner Office" in the New York Times, in which successful businesspeople muse about leadership. His philosophy of leadership is simple: honesty and consistency.

"Don't tell one thing to one group of doctors and something else to another," he says. That approach was essential when the Penn medical system took over Pennsylvania Hospital in 1997, and he had to merge the two cultures and ways of practicing medicine.

What lessons has he learned along the way?

"Stay humble. Medicine can be very humbling; you can't know everything. Know what you don't know and ask for help when you need it."

"Never stop learning. You owe this to your patients. Work hard to stay current."

"Take the opportunity to teach and mentor younger physicians; they in turn will teach you and keep you on your toes."

"There is more to being a doctor than knowing the right diagnosis or the right medicine. Sometimes there is no medicine, or a medicine is not what the patient needs. Sometimes comfort, support, and caring need to be part of, or even all of, the treatment."

I asked Buckley to pretend I was his son. What advice would he give me about achieving well-being?

Balance, he said, is "critically important" - between career and family ("I am fortunate to be married to my best friend, and she and my children have always kept me grounded and focused on the right things"), between mental and physical (Buckley runs three miles four days a week and has completed several sprint triathlons).

"I think people who are content are happy with what they have," he said, "and do not focus on what they don't or can't have."