"Funny thing about show business,” Harry Connick Jr. says. “Opportunities don’t just present themselves. You have to seek them out.”

Connick is explaining how a New Orleans piano prodigy — he started taking lessons at age 3 and playing publicly at 5 — parlayed that talent into being not just a Grammy-winning and multiplatinum-selling singer but also a film actor (“Memphis Belle,” “Dolphin Tale,” “Hope Floats”), television actor and personality (“Will & Grace,” “American Idol,” his Emmy-winning concert specials and “Harry,” his Daytime Emmy-nominated talk show), and a Tony-nominated Broadway lead actor (“The Pajama Game”) and composer-lyricist (“Thou Shalt Not”).

“Like anything in life, you have to want to do something and go through with it,” Connick says. “If you want to be a movie actor, you have to spend time going on auditions and going to meetings and developing projects. Nobody’s going to come to you.

“Most people who are successful in this business had to think for themselves and make opportunities happen for themselves — at least, anybody with longevity.

“But I wanted to be on Broadway. I wanted to be a composer and actor on Broadway and in films and TV and all that stuff. So those are all things that I kind of put my mind to.”

Connick is currently in music mode, on tour celebrating the tricentennial of his hometown, playing music associated with the Big Easy, plus — given the time of year — perhaps some holiday favorites as well. His show visits the Stifel Theatre on Dec. 20.

“I just want to do songs that let people into my version of New Orleans,” he says. “There’s traditional jazz, there’s brass band, there’s funk music. We could probably play for hours and hours just playing different styles. So we try to give a nice little representation of music that I grew up with and that was important to me.”

Connick’s musical education helps explain the polished yet intuitive performer who gained fame in 1989 with the romantic soundtrack to the film “When Harry Met Sally.” Among his teachers were Ellis Marsalis, paterfamilias of the jazz-playing Marsalis clan — Wynton, Branford, Delfayo and Jason — and an educator at the New Orleans Center for the Creative Arts, which Connick attended.

Meanwhile, Connick’s piano teacher was James Booker, the larger-than-life musician whom Dr. John famously called “the best black, gay, one-eyed junkie piano genius New Orleans has ever produced.”

“It was a trip being around both of them, but in completely different ways,” Connick says.

“I was with Ellis every day for years and years. He did more than teach piano. He taught us theory and everything. He relied very heavily on the discovery process. He based the information he gave you on your capacity to understand.

“I remember calling him at his house one time saying, ‘Man, I noticed when I keep this one common tone in my left hand, I can move these other notes around, blah-blah-blah,’ and he said, ‘Yeah, yeah.’ And I was like, ‘Why didn’t you teach me that?’ And he said, “Because you were going to figure that out on your own.’

“It takes a really specific type of person to understand that and to be able to play that long game.”

Booker, on the other hand, was more of a wild card. “He was about, you know, just hanging out and trading licks and showing each other different things,” Connick says.

“It was just such an incredible, beyond-belief luxury to spend time around them as a piano player. It would be like, if you were a basketball player, growing up around Michael Jordan and LeBron James, if they had completely different teaching styles.”

Doing his homework

That well-rounded education stood Connick in good stead both in New Orleans and later in New York. In either place — or petty much anywhere else, as any jazz musician will tell you — the real professionals don’t have time for those who don’t do their homework.

“Sometimes I would show up at a gig, and we’d be playing these traditional jazz tunes,” Connick recalls. “Some of them have real complicated forms: They’re not like, typical A-A-B-A forms, they’re A-B-A-C, B-A-D-D, you know, crazy stuff. So by the time your solo comes around, if you don’t know the song, it’s quite obvious to everybody that you couldn’t figure the form out.

“You have about four or five choruses to learn that song. You have the melody and the trumpet solo and the clarinet solo and then the piano solo, and everybody stops playing but the bass player and the drummer.

“And if you don’t know it, they just won’t call you anymore.”

Of course, these were seasoned jazz veterans that Connick was playing with. “These aren’t teenagers,” he says. “I was 14, but some of these guys were in their 50s and 60s. They were playing this music when it was being invented. They don’t have time for some novice.”

Connick carries that attitude with him today in his own band. Many of its members have been with him for years — decades even.

“They can do anything,” he says. “This group of musicians is so flexible. That’s why we change it up every night. Everybody’s very calm. There’s a word for what they’ve got: equipoise.

“That means, like, when Muhammad Ali used to fight and he would be incredibly relaxed but incredibly powerful at the same time. My guys are at full intensity the whole show. You can go anywhere, and they never even bat an eye. That’s one of the benefits of having those long-term relationships.”

Connick makes his musicians a major part of the show and doesn’t mind if they step out a little on their own.

“We’re all out there entertaining together,” he says. “That comes from New Orleans, too. It was always about a group effort. I welcome them to try to take the show from me at any given moment. If they can get standing ovations in the middle of the show, that’s great. It’s my problem if I can’t get the audience back. I like that kind of challenge.”

Giving back

These days Connick lives in Connecticut but says he gets back to New Orleans “every month or six weeks or so.” He stays with his dad, and they go out to dinner. Otherwise, he keeps a fairly low profile there, except to occasionally perform and also do the kind of charity work that is close to his heart.

Connick and Branford Marsalis are founders of Musician’s Village, a community in the city’s Upper Ninth Ward that provides homes for musicians displaced by Hurricane Katrina. It contains the Ellis Marsalis Center for Music, a public facility that includes classrooms, a concert hall and a recording studio.

“In fact, we have a board meeting today,” he says.

Of the city itself, which, 13 years after Katrina, is still in recovery mode, Connick says, “There are some parts of the city that haven’t come back and probably won’t. But the city itself has come back, and it’s way stronger than it ever was when I was there.

“What makes New Orleans New Orleans will never change. The history is the thing that people celebrate the most, and that is locked in. Despite the indescribable tragedy that was Katrina, there was some good that came out of it, too, and I think New Orleans was and is headed in the right direction.”

When his tour wraps up — St. Louis is the last city on his itinerary — Connick will have to decide what to do next. His last album was 2015’s “That Would Be Me,” but he’s not sure when the next one will appear.

“We’re in that process right now. It’s an interesting time, like where everything goes into the lab,” he says. “I have to go into the studio and make a record. We have a bunch of Broadway and film and TV projects. A lot of stuff is being worked on. We’re just getting ready for the next phase.”

And finally, of his TV show, which ended its two-year run in May, with the last of its reruns airing in September, Connick says that, despite its cancellation, “It was an unbelievable experience.

“If you think about entertainment and daytime television, actually being able to do what you set out to do is really, really hard. I set out to do a show that was positive: no politics, just celebratory and inspirational, and with music in the daytime, which had never been done and probably never will be done again to that degree, where the talk show host is also the bandleader. I mean, that just doesn’t happen.

“We had an amazing two years, and it was incredible. I was lucky to have that opportunity, and now it’s onward and upward. We’ll do the next thing. But that was a lot of fun.”