Yannick Nézet-Séguin, finally ready for his close-up

Fresh from appearing with the fabled Vienna State Opera, Yannick Nézet-Séguin was at the epicenter recently when shockwaves rippled through the cultural world, as that company's chief conductor, Franz Welser-Möst, abruptly walked out with minimum explanation.

"Surreal" and "very quiet" was Nézet-Séguin's report from the belly of the beast. But after his successful debut in the Austrian capital conducting The Flying Dutchman, should Philadelphians worry that Vienna is prowling after the Philadelphia Orchestra's popular and still-newish music director, as the Metropolitan Opera has long been rumored to be doing?

"My time [in Vienna] was very enjoyable and there are talks of my coming back to conduct more opera, but ... I'm not in search of a new title." (In fact, he has stepped down as principal guest conductor of the London Philharmonic.)

His third Philadelphia Orchestra subscription season begins Friday, with pianist Lang Lang the featured artist. After the more conservative years shadowed by the institution's bankruptcy, Nézet-Séguin has devised some of his most personal programs yet, several drawing on his longtime commitments in Rotterdam and his native Montreal, others showing him in completely new musical worlds.

"I'm not the kind of person to arrive and say that I'm changing everything. Being a leader of an orchestra is a much more interactive process than we might think," he said. "This is the first season where I had sufficient tools - knowledge of the audience, knowledge of the orchestra - to know how I wanted to direct the ship."

What that looks like: In his post-concert talk-back sessions with audiences, British symphonist Ralph Vaughan Williams surfaced. In response, Nézet-Séguin has scheduled Vaughan Williams' infrequently heard 1935 Symphony No. 4, said by some to reflect the composer's long-delayed post-traumatic stress from his service in World War I, for this period of global commemoration of the war's centenary.

More casual is his January Shostakovich concert: Having had one of his bigger Philadelphia successes with the Russian's Symphony No. 5, he pairs Beethoven's Symphony No. 5 with Shostakovich's lighter Piano Concerto No. 2 and The Gadfly.

Though Nézet-Séguin has long showed his colors as a choral conductor - and will be reprising Bach's St. Matthew Passion from the first season - his early years as a church musician have prompted this season's more prominent use of Verizon Hall's Fred J. Cooper Memorial Organ - three different concertos for the instrument in a single weekend.

The wildest organ showcase - Janacek's Glagolitic Mass - slipped out of his hands and into those of guest conductor Alan Gilbert. "He was very excited about it," Nézet-Séguin said, "and I can't do everything."

Nézet-Séguin's overarching concept is the "40/40 Project" - 40 works not heard in Philadelphia Orchestra subscription concerts in the last 40 years, in anticipation the conductor's 40th birthday on March 6, 2015. The idea is came out of his examination of the orchestra's repertoire database.

"It started with 20 pieces in the past 20 years," he said. "Then we decided, let's go for 40. It was like a sportive challenge."

That concept also accommodates new work. Guest conductor Robert Spano, a longtime champion of Jennifer Higdon, chose the composer's Pulitzer-winning Violin Concerto, while another, Gianandrea Noseda, will conduct Michael Daugherty's all-American, unconventional tuba concerto Reflections on the Mississippi with the orchestra's Carol Jantsch.

Other 40/40 pieces seem to arrive on a technicality: Could Respighi's Ancient Airs and Dances be unknown to local audiences? Somehow, the second suite of that popular collection slipped through the cracks. Lucky happenstance marks the Mark-Anthony Turnage Piano Concerto, a fun, nasty refraction of jazz that Nézet-Séguin premiered with exceptional success last season in Rotterdam and is bringing here with pianist Marc-André Hamelin.

He is acutely conscious of the relationship he is now in a third season of fostering.

"I try never to forget the trust that needs to exist between the audience and the orchestra," he said. "It's something precious that needs a certain time to create. Losing it takes much less time."

So his biggest and riskiest program is Leonard Bernstein's Mass: When premiered in 1971, it was heard as a forced attempt at counterculture topicality. Only in recent years has the sprawling piece, with its guitarists and dancers, emerged from its radical-chic stigma.

Nézet-Séguin hears Mass as a visionary blending of genres. Expect more Bernstein in the future.

That Bernsteinesque mixture of high and low extends to the music director's approval of the orchestra's more down-market presentations in his absence, such as the faux-Beatles Classical Mystery Tour - under the heading of wider community engagement. Recently named principal guest conductor Stéphane Denève went so far as to conduct John Williams' suite from Close Encounters of the Third Kind.

Then again, Denève and Nézet-Séguin are of a generation that hears Hollywood film music as worthy of something more than pops concerts.

Often mentioned among the generation of young conductors leading top orchestras, Nézet-Séguin may look like the youngest - though he's midway between Los Angeles' Gustavo Dudamel (33) and New York's Gilbert (44) - but he so far seems immune to the critical backlash that some of them have experienced.

He can't really think about that. "That would be like driving to avoid having an accident," he said. "Believe me, there are still many people for whom I am overrated. There will always be those people. I don't think about how to place anything in my career, but try to be there in the moment."

Hearty support comes from his retirement-age parents and his partner, cellist Pierre Tourville (who keeps him from sightseeing overload while on tour). So Nézet-Séguin isn't doing it alone.

"I've always been a very loyal person, stable in my relationships," he said. "I don't need to be over-protected from the outside world. But it's important to have this connection with people around me and then just concentrate on making music."

And in the wake of an illness that sidelined the 5-foot-5 conductor for two months last season, his Facebook page is full of photos of him after a sweaty run in T-shirt or tank top, showing why opera star Joyce DiDonato calls him "Mighty Mouse."

Clearly, he's forging a new "type" for symphonic conductors, so much so that the Philadelphia Orchestra website mostly refers to him simply as "Yannick."

In that spirit, would he ever go shirtless on Facebook? No, he says - "but I have nothing to hide."