"Without a Trace" (search) star Anthony LaPaglia (search) says making television-career decisions based on a script for a one-hour pilot is an extremely tough call.

"It's a massive crapshoot," LaPaglia, who plays FBI agent Jack Malone, told The Post.

"When they put us up against 'ER,' I thought, 'Whoa, that's it, pretty much - we'll be on the air for five or six weeks and be gone.' That was kind of my expectation."

Wrong. The CBS series' runaway success clearly validates LaPaglia's hunch to sign on, based on his fondness for the show's premise.

"I liked the missing-person thing, I liked that you kind of piece together a psychological profile and you reconstruct their life - that you get to see it happen on screen," he said.

No stranger to television - he was a cast member on "Murder One" (search) seven years ago - LaPaglia knows that the fast pace of television brings its own batch of surprises.

"From week to week, you have no idea what's going on," he said. "I'll pick up a script and go, 'Oh, I have a wife!' or 'Oh, I have two kids!' "

That "crapshoot" element pretty much describes the spirit behind LaPaglia's foray into acting years ago.

A native of Australia, LaPaglia was a shoe salesman when he decided, in his early 20s, to move to New York City. Shortly before he left his homeland, he attended a theater performance that would change his life direction.

"I found the experience so riveting, a light bulb went off and I thought, I would love to do that," he said.

"It was one of those moments where I was really mesmerized and the audience kind of became one, collective organism. They were quiet in the same place, they laughed in the same place. It really attracted me in a big way."

LaPaglia studied his craft in Manhattan, the place he still calls home.

"At the beginning of my career, I didn't have a resume, I started at the bottom," he said. He worked extensively in theater and, well after infiltrating film and television, took home a Tony award in 1998 for his role in "A View from the Bridge."

In a strange twist of fate, he got the role on "Frasier," (search) playing Daphne's loutish brother Simon Moon - those performances earned him an Emmy - because a casting director remembered seeing him play a virtually identical character on stage, in a play called "Bouncers" years earlier.

LaPaglia recalled "Frasier" producers' shock when he turned up at their door.

"At first, they went, 'Are you kidding? The guy plays gangsters'!"

LaPaglia attributes his longevity, at least in part, to diversifying.

"I've never been a medium snob," he said. "I don't care what medium, so long as the material is good. I never cared what anybody thought."

In addition to his real-life role as a new father - he and his wife, actress Gia Carides (search), have a little girl - LaPaglia has added to his resume the title of executive producer of an independent film called "Winter Solstice" which, he said, taps "into that suburban life of quiet desperation."

Fans equally desperate to know where agent Malone is headed this season will get no details from LaPaglia. The show's writers told him Malone would have a bit of a struggle with his ideological convictions.

"That's pretty broad," he said.