SANTA MONICA, Calif. -- A conversation with J.J. Abrams is more like a series of interruptions and distractions, punctuated by occasional exchanges of dialogue. The latest diversion to appear on his iPhone screen one evening in March, as he unwound here at the offices of his Bad Robot production company, was a photograph sent by his producing partner, Bryan Burk, of two tip jars side by side on a coffee-shop counter: one labeled "Star Wars," and the other "Star Trek."
Here, in a discussion about his ever-expanding film and television empire, Mr. Abrams, 46, the prolific director and producer, had to stop and laugh at this encapsulation of his world, and a seemingly one-or-the-other decision he faces.
Life would be challenging enough for Mr. Abrams as he puts the finishing touches on "Star Trek Into Darkness," the long-awaited sequel to his 2009 reboot of "Star Trek."
The arrival of Mr. Abrams' first "Star Trek" film, which cast fresh-faced actors such as Chris Pine and Zachary Quinto in the roles of Kirk and Spock, did more than revitalize this dormant, decades-old space-adventure series. It vaulted Mr. Abrams, a creator of television shows such as "Lost" and "Alias," into the vanguard of directors who could successfully run the summer movie spectacles that are the lifeblood of Hollywood studios.
Then, just as he was settling into his captain's chair on the starship Enterprise, Mr. Abrams rocked the geek-culture universe with the announcement, after some feints, that he will be directing a seventh film in the rival "Star Wars" saga, planned for 2015.
It is an assignment Mr. Abrams, who grew up in Los Angeles obsessed with movies such as "Star Wars" and "Jaws" (not to mention "The Philadelphia Story" and "Ordinary People"), said he could not pass up. But no one in his camp -- least of all Mr. Abrams himself -- knows how this choice will affect the new "Star Trek" movie or a director who never met a vintage action franchise he could resist.
"There are, I'm sure, people who would say I've never been very good at anything," Mr. Abrams said, speaking in a fast-slow-fast, start-stop-start delivery that mirrors his work habits. "But I've also never been very good at focusing on one thing. It just seems to be my MO."
When Mr. Abrams' original "Star Trek" sold $385 million in tickets worldwide, it created the expectation that he would promptly reunite his creative team and get to work on a sequel, and this raised problems.
First was the question of whether Mr. Abrams and his collaborators -- formerly outsiders who had to prove to audiences that they could take over "Star Trek," now its established stewards -- could surpass themselves in a second go-round.
"When you're operating from a place of, 'We trust you now,' there's much further to fall," said Damon Lindelof, a writer and producer of "Star Trek Into Darkness" and a creator of "Lost." "I always like operating from a place of lowered expectations."
Narratively, Mr. Abrams' "Star Trek" used a sly time-travel subplot to establish its young Starfleet officers without annihilating the 40 years of story lines that preceded the film. But it also destroyed Spock's home planet of Vulcan -- an occurrence Mr. Lindelof called "our 9/11 event in the 'Trek'-verse" -- and this seemed to demand further consequences in the sequel.
"Into Darkness" delivers this retribution through a new nemesis played by Benedict Cumberbatch, the star of "Sherlock," whose vendetta against Starfleet hints at a more complicated agenda behind his murderous acts.
"The reasons for terrorism in any situation are a little more complicated than someone just hating our freedom," said Roberto Orci, who wrote "Star Trek" with Alex Kurtzman, and who both return on "Into Darkness." "We wanted the villain to be equally nuanced, to the point where some might not even call him a villain."
But in the years since the first film, gathering the "Star Trek" brain trust in the same room became an exponentially complicated task. Mr. Lindelof was finishing "Lost" and working on the science-fiction thriller "Prometheus"; Mr. Kurtzman and Mr. Orci were producing their own projects, including Mr. Kurtzman's feature-directing debut, "People Like Us"; and Mr. Abrams was making his coming-of-age fantasy "Super 8."
The uncertainty of whether Mr. Abrams would direct this sequel was perhaps the greatest challenge of all. "Our collective goal," Mr. Kurtzman said, "was to make it something he would want to do."
This strategy seemed to win over Mr. Abrams, who spoke about "Into Darkness" as if it were a spiritual quest or lifesaving surgery. "Despite wanting to do other things," he said, "suddenly I found myself feeling like, 'I cannot not direct this movie.' "
If his role as master of the "Star Trek" and "Mission: Impossible" film franchises -- both are produced by Bad Robot -- seem overwhelming, Mr. Abrams said it was a welcome alternative to his younger, hungrier years, "when I was working in restaurants and ice-cream stores and comic-book stores."
Although Mr. Abrams suggested in interviews last year that his commitment to "Star Trek" would make it nearly impossible for him to direct "Star Wars," he said his thinking evolved as he worked on "Into Darkness" and his schedule became clearer.
"It wasn't as if they offered it to me outright and I passed," he said of his conversations with Lucasfilm. "It was early discussions, and I just felt like it was not the right thing to even consider." But "a number of weeks, if not months, went by in between those calls," he said, "and it was easier to actually think about."
For his "Star Trek" colleagues, this proved a surprising and bittersweet development.
Mr. Lindelof said he was "profoundly thrilled" that there would be new "Star Wars" movies and that Mr. Abrams would be directing one. But seeing Mr. Abrams poised to jump to a new swashbuckling, intergalactic epic, Mr. Lindelof seemed unsure if audiences would still care about the swashbuckling, intergalactic epic they just finished.
"I wonder if 'Star Wars' is now going to eclipse 'Star Trek,' " Mr. Lindelof said, "so that when this movie comes out and people are asking us questions, is everyone going to be asking me about 'Star Wars'?"