Actor Rob Morrow sat in his trailer puffing on a Cuban cigar, a gardenia-scented candle wafting from a table.

Still boyish at 46, Morrow doesn’t look all that different from his 1990s character of Dr. Joel Fleischman, the adorably whiny New Yorker stuck in the Alaskan sticks on “Northern Exposure.”

In “Numb3rs” on CBS, Morrow plays an even more unusual Jewish fish-out-of-water: FBI agent Don Eppes, who solves crimes along with his math genius brother (David Krumholtz) and retired father (Judd Hirsch). All season, Eppes has been exploring Judaism in an attempt to grapple with job-related moral dilemmas.

He argued with his secular brother about his spiritual journey, attended services and lectures at Wilshire Boulevard Temple, cited concepts such as “natach lach” (focusing on issues within one’s control) and faced off with an old nemesis inside his synagogue.

“I kind of forced the issue,” Morrow said of his character’s Judaism. Morrow said it had bothered him that the show — just over halfway into its fifth season — had never clearly identified the Eppeses as Jewish, even though all three lead actors had previously portrayed Jews on screen. At a function attended by “a number of CBS types,” Morrow made his point by playfully asking how many present saw the characters as Jewish.

“Everyone applauded,” he recalls with a laugh. “But initially there was a lot of ambivalence about expressing that side of the Eppeses — perhaps because of a fear of anti-Semitism, but mostly because these shows are built for the largest possible audience. My bent was, ‘Why deny what is obviously there in the name of versatility?’ It’s more interesting to say, ‘We can’t get away from this, because if you don’t think these characters are Jewish, there’s something wrong with you — so let’s embrace it, and use it to distinguish ourselves among all the other procedural crime dramas on TV.’ ”

Added Morrow: “I thought his [Jewish] journey  would be an organic way to take the show in a new direction and allow the expression of some other colors beyond shows like ‘CSI’ or ‘NCIS.’ ”

Executive producer Ken Sanzel liked the idea. “I thought it could be a story not so much about a person finding Judaism as about a person who feels lost trying to find a new set of guidelines,” Sanzel, who is Jewish and an ex-cop.

Morrow’s best-known characters share a distinctive sense of longing. The actor said he identifies with this desire to fill a spiritual and psychological void.

“My parents divorced when I was 9, which was my fall from grace — it was like getting kicked out of the Garden of Eden,” he said. “That defined me in so many ways I had to overcome — suffice it to say I spent many years in therapy talking about it.”

When his father moved out, the rest of the family relocated from their middle-class New York home to a series of shabby apartments on the fringes of luxurious neighborhoods in and around Scarsdale, N.Y., where his mother insisted they “keep up appearances.” The young Morrow acted out by committing petty thefts, stealing cars and joyriding.

After his Reform bar mitzvah — an unsatisfying affair he prepared for by memorizing Hebrew prayers phonetically — Rob saw “Grease” and was mesmerized by the rebel from the wrong side of the tracks. “From then on I wanted nothing except to become an actor,” he said.

His big break came in 1990 with “Northern Exposure,” when he portrayed a character who, for all his kvetching, represented an alternative kind of hero. In the era of “Seinfeld’s” self-denying Jewish characters, Morrow became the most obvious member of the tribe on TV.

His portrayal of a Jew was even more nuanced in the 1994 Robert Redford film, “Quiz Show,” an expose of the 1950s “Twenty One” scandal in which he played the Harvard-educated prosecutor, Richard Goodwin.

In his trailer, Morrow takes a final puff on his cigar, then crosses the street to the Korean Philadelphia Presbyterian Church — which decades ago housed Sinai Temple and nicely doubles as the interior of Eppes’ synagogue because it retains its ornate stained-glass windows decorated with Hebrew lettering and Stars of David.

“For my satisfaction we don’t go into Don’s ‘Jewish’ scenes enough,” he said, “but the problem becomes, you’ve got 42 minutes, and the genre requisites are paramount. Of course, at this point Don is still exploring and seeing if Judaism is right for him. I don’t think he’s said ‘I’m Super Jew, and everyone’s going to daven now at the FBI.’ I think he’s trying to get a grasp on it, and the dividends are more philosophical and spiritual.”

“Numb3rs” airs Fridays at 10p.m. on CBS.