It’s in an elevator that Tom knows Summer is the one.

As they ascend to the office of the greeting card company where they both work, Tom Hansen (Joseph Gordon-Levitt) nonchalantly bops along to The Smiths’ jaunty, jangly “There is a Light That Never Goes Out” gently escaping from his earbuds. Summer Finn (Zooey Deschanel) is new to the office but has been noticed by anyone attracted to a fetching fringe, including Tom, who’s besotted at first sight. She hears the song, perks up, says how much she adores The Smiths, and begins to quietly, instinctually, sing along to one of his favorite bands. He’s thinking duets; she’s thinking, “Where did my copy of ‘Meat is Murder’ go?”

That’s because “(500) Days of Summer” has almost instantly let the viewer know in omniscient narration that he isn’t the one for her.

So The Smiths are like the houseband for the tone of the film. With a complex mélange of styles and emotions, their songs can be effervescently romantic and sly with an up-tempo rhythm section thumping out a sprightly beat; but then the tunes can become demonstrably maudlin as the guitar sidles around despairing, longing lyrics. If you’re mourning a relationship’s demise, an empathic Morrissey, simultaneously vulnerable and defiant, understands why you’re mewling at the rainy window pane. Director Marc Webb successfully chooses an intriguing storytelling device to capture the ever changing moods of Tom and Summer’s fated love affair that mimics the band’s spirit without taking on the full despondent histrionics of a Smiths track. Instead of a standard linear approach, Webb, who makes a fine feature-film debut, jumps in between days, capturing the undulations of the romantic to and fro, so that random days throughout the 500 of the relationship keep popping up. Just from the beginning, day 290 is followed by days 1, 3, 4, and 8, with a leap to day 154 and then back down to day 11. The back and forth isn’t dizzying. Webb and writers Scott Neustadter and Michael Weber nicely and understandably weave between the ecstasy of the earliest getting-to-know-yous and the anguish of a couple fraying into the past tense. And while Tom’s trauma crouches coiled with just-around-the-corner expectation, “(500) Days of Summer” is still a decidedly fanciful, funny and romantic film. Blessed with a sensational soundtrack which includes Mumm-Ra, Carla Bruni and The Pixies, the movie is sweetly crafted by moments such as an uproarious musical number choreographed to a Hall & Oates ditty, a “Seventh Seal” parody that executes a new laugh for an old gag, and a trip to IKEA which goofs on domesticity. Cinematographer Eric Steelberg drapes Los Angeles with a timeless, dreamy charm. The ageless vibe is accentuated when Tom, who owns a car, takes the train up the coast where he unexpectedly runs into Summer onboard. However, despite the marching bands, the clever Belle and Sebastian references and the slow dances at a co-worker’s reception, the bittersweet is never too far removed; day 34 is grafted right next to day 303.

But, quite frankly, “(500) Days” is also an opportunity for the best American actor under the age of 30 to excel in expanding his repertoire, and, hopefully, his following. An industry veteran since childhood, Gordon-Levitt found fame in the 1990s as the precocious Tommy Solomon on “3rd Rock from the Sun” and the smitten Cameron in “10 Things I Hate about You.” But then the Californian put his career on hiatus, set off to New York, and enrolled at Columbia. He returned to Los Angeles grown up and invigorated, conscientiously taking on complex roles with a ferocious zeal, as though he spent his days back East sitting in Washington Square Park reading Baudelaire, listening to Bad Brains. It’s a resume of small budgets and vast rewards; with “Mysterious Skin,” “Brick,” “The Lookout,” and now “(500) Days” he’s put together one of the most impressive catalogues of perceptive performances this decade.

Too damaged to be cute, and too disinterested in a personal trainer to be a hunk, Gordon-Levitt is his own construal of handsome. He has a naturally saturnine face with wounded eyes that can thin easily into cynical slits and a tight mouth gifted for emoting melancholy. He has the presence of being young and old at once, and in “(500) Days” Gordon-Levitt blends these attributes in an unaffected, versatile portrayal of yearning. Trained as an architect, Tom has been sidetracked by toiling, successfully, for more than three years as a greeting card writer. Gordon-Levitt doesn’t play Tom as either angry or tortured; he’s pining for a partner and dissatisfied with his job, but he’s relatable in both his wisdom and his naivety. The Joy Division T-shirt fits hand-in-glove but the script and his discerning performance don’t oversell the self loathing of someone whose Hallmark aphorisms ring mockingly hollow to their own life.

The story doesn’t give Summer an opportunity to expound like it gives Tom. It’s one sided, but it’s the point (and the title) of the film; this is about Tom. He’s got two buddies to share his thoughts with as the relationship vacillates, and even a wise prepubescent little sister. So when Summer says to Tom, “we’re just friends,” we meet none of hers. A meaningful split screen sequence of expectations and reality isn’t the expected “he said/she said” but an insightful view into Tom’s competing visions. Already on the shortlist of the screen’s cutest chanteuses, Deschanel – with Hockney blue eyes as startling and vast as Crater Lake – is a credit to her role as the It girl for the IT crowd and shares an admirable, touching chemistry with Gordon-Levitt, who proves with her assistance that he’s got leading man flair along with his already established acting prowess.

Perhaps only Ryan Gosling resonates as a contemporary of comparable talent to Gordon-Levitt. (You could even see the two trading roles successfully; Gordon-Levitt flourishing in “Lars and the Real Girl” with Gosling succeeding in “The Lookout.”) While granite-chiseled lunks like Channing Tatum, Paul Walker and Shia LeBeouf have been hogging the box office this year, it would be heartening to see an actor of the pedigree of Gordon-Levitt, who assiduously and consistently selects his vital roles in engaging and lingering films, gain wider appeal. If one is wondering when this should be, then, in the words of The Smiths, “How soon is now?”