NEW YORK — It is hard to describe the hysteria that was whipped up by the new NBC drama “Dr. Kildare” and its 27-year-old leading man, Richard Chamberlain.

Adding to the excitement was the harmonic convergence that found a rival doctor drama, “Ben Casey,” arriving in ABC’s lineup just four days after “Dr. Kildare” debuted on Sept. 28, 1961.

Both shows erupted as smash hits. Both launched out-of-nowhere heartthrobs. Then, as if on cue, each sputtered to a finish five seasons later.

Rugged, swarthy Vince Edwards would never again enjoy his prominence as Dr. Casey. He passed away two decades ago at age 67.

But a happier fate awaited Chamberlain, who, spared the typical flare-out of an overnight sensation, followed up his stint at Blair General Hospital with a varied and distinguished slate of films, TV and theater. Today, at 80, he is still working and, thanks to facial exercises and defiant genes (but no cosmetic work, he vows) retains the dreamboat looks of an elder James Kildare.

Through Dec. 14, Chamberlain can be found onstage in an off-Broadway production of the David Rabe black comedy “Sticks and Bones.”

In his small but pivotal role, he plays Father Donald, who is called in to counsel the son — a traumatized Vietnam war veteran — of co-stars Holly Hunter and Bill Pullman.

“Then all hell breaks loose,” says Chamberlain, adding with a chuckle, “I’ve played a lot of priests over the years.” Not the least of them was Father Ralph de Bricassart, that passionate priest of “The Thorn Birds,” the 1983 miniseries whose success on the heels of likewise top-rated “Centennial” and “Shogun” certified Chamberlain as The King of the miniseries genre.

“A job like this is ideal,” says Chamberlain before a recent performance as his current Man of God. “I’ve got one-and-a-half scenes, but a really GOOD scene!”

Then he raps a wooden table conveniently in reach, and laughs again.

“I’ve been so lucky,” he says. “I’ve been acting for 55 years — meeting the right people, getting the right advice, getting the right jobs.”

At the same time, he has traveled a long and winding spiritual path, an odyssey he recounts in his 2003 memoir, “Shattered Love.”

One thing he learned along the way: Love is at the root of it all.

“I think love is the source of wisdom, of strength, of intelligence,” he says. “It’s a presence that exists within us and without us. I think it’s all of that. It’s not a box of chocolates.”

In writing his book, Chamberlain had set about to put such thoughts on paper. But at the same time the book became an unintended forum for his coming out (today, he remains in a decades-long relationship with actor-producer Martin Rabbett).

“Back then, at age 68, I still had a sense that there was something wrong with me,” he says. But as he was writing, “almost as if an angel had come through the window, there was this sense of a presence saying, ‘All of the stuff you’ve been worrying about for all those years is bulls—-.’ And suddenly, I let go of all of that. It was like a miracle.

“I think I came into this life with stuff to work out,” he muses. Growing up in a middle-class section of Beverly Hills, California, Chamberlain wasn’t just shy, but, as he puts it, “terrified. I didn’t like real life. But the movies — man, I loved to go to the movies! That’s where I wanted to be.” Acting seemed his obvious calling. “Pretending to be other people was something I did anyway.”

In college, he landed a role in a comedy by George Bernard Shaw, and in a key scene, “Somehow I just broke through and the place went crazy. I thought, ‘Dammit, I can be an actor!’”

Within a few years he was — and much more.

“It was amazing!” marvels Chamberlain, still full of wonder at having hit the “Dr. Kildare” lottery. “I used to get 12,000 letters a week. I didn’t entirely buy the fact that I was thought enchanting by a lot of people. But I enjoyed it tremendously, even as a part of me went, ‘Realllly?!’”

After the series ended in 1966, Chamberlain made a crucial “what now?” decision. He moved to England to do theater, and was soon onstage in the title role in “Hamlet.”

He won critics’ approval. But offstage, “I began to notice that my way of being a ‘winning personality’ wasn’t that winning anymore. I could fool a lot of Americans, but I couldn’t fool many Englishmen.”

Fooling people — off the job, at least — isn’t nearly such an issue for Chamberlain these days.

“The journey toward a sense of well-being has been a long one,” he says. “But over the years, I’ve found out how to just be a person. It’s a great relief.”