Any “As You Like It” rises or sinks with its Rosalind. In fact, it could be argued that the play sinks for a while because of its Rosalind. She’s too good for Shakespeare, in a sense: The character is so forceful, so articulate, and yet so aware of her own foibles that he feels compelled to hide her behind a batch of comic rustics in the second half, sabotaging the play’s momentum.

Lynn Collins, who was triumphant as Portia in last year’s underrated “Merchant of Venice” film, makes an equally wonderful Rosalind here. Even when Mark Lamos’s staging flags, Ms. Collins’s bewitching charms keep the overall tone at a pleasant hum. Ms. Collins’s gender-bending skills were evident in “Merchant,” but she takes a different approach here.

This Rosalind starts out as a giggly, eyelash-batting princess, and Ms. Collins and Mr. Lamos wisely keep her subsequent transformation – in which she dons men’s clothes to befriend and beguile the exiled Orlando (James Waterston) – within plausible levels. She can lower her voice and swing her elbows all she wants, but this Rosalind has a hard time keeping her hips still when Orlando gets close. When Orlando departs after one stimulated wooing, she immediately tears off her cap with a gasp, her long hair tumbling down her shoulders; it is all Rosalind can do to keep her femininity in check.

The key romantic pair in this play is a mismatch, with Rosalind scheming and charming circles around the hapless Orlando. Most productions struggle with this, but here the balance is unusually skewed. Mr. Waterston may have the somber jawline and leaping eyebrows of his father, Sam, but he also shares a pinched vocal timber that gives this Orlando a panicky, almost sickly cast. “What passion hangs these weights upon my tongue?” Orlando laments early on after an ineffectual meeting with Rosalind. Whatever it is, the weights remain throughout the play.

The other big disappointment is Richard Thomas as the jester Touchstone. Mr. Lamos and Mr. Thomas have successfully collaborated on some treacherous plays in the past, from Ibsen’s “Peer Gynt” to Albee’s “Tiny Alice,” but here they are unaccountably out of sync. “I shall ne’er be ware of mine own wit till I break my shins against it” is a more accurate self-estimation of Touchstone’s comic gifts than usual. Mr. Thomas unleashes a barrage of self-satisfied grins, crotch jokes, and capering dance steps. It does little to mask the spectacle of a comic actor battling rather than serving the text.

Brian Bedford, as canny a veteran as the stage has seen for some time, steals scene after scene as Touchstone’s cohort, the melancholic Jacques. Mr. Bedford finds laughs in the most unlikely spots without ever betraying Jacques’s saturnine nature. Jacques promises to “through and through / Cleanse the foul body of th’ infected world / If they will patiently receive my medicine,” and his dour ministrations are a tonic to all around him. Nearly every actor is at his best when sharing the stage with Mr. Bedford.

Inevitably, the “country copulatives” (as Jacques memorably calls them) move front and center, with regrettable consequences. Like so many productions of the play, this one runs aground as the romantic travails of Touchstone, Audrey, Silvius, Phoebe, William, and Orlando’s reformed brother all crowd Rosalind and Orlando into the background. Mr. Lamos regroups with the escalating Act V love confessions among our heroes and two of the rustics.

These overlapping declarations take on the propulsive rhythms of a fugue, and William Finn and Vadim Feichtner’s score chimes in shortly thereafter. They have composed a shimmering underscore, dense with the teasing dissonances and swelling crescendos one more commonly hears on the silver screen. Mr. Lamos sprints the rest of the way, juggling the various couplings with a surefooted sense of pacing. He gets an unexpectedly delightful lift from Sean Curran’s choreography.

Riccardo Hernandez’s handsome set converts the Delacorte into an ornate map of the cosmos, complete with fanciful constellations hanging overhead. All the world may be a stage, as Jacques has it, but here all the stage is a world and then some. This arresting visual concept is more successful than Mr. Lamos’s occasional use of stuffed sheep and goats, accompanied by offstage bleating, to depict the rustic setting. The gilded trees do fit in well with the Central Park background, however, and Peter Kaczorowski’s lighting design coexists particularly well with the shifting natural light of Central Park.

It is taking nothing away from Mr. Bedford’s delightful dyspepsia, the sparkling score, or the handful of strong supporting players to say that this production belongs to its Rosalind, as any “As You Like It” must. And the assured Ms. Collins makes it clear that a galvanizing young talent has arrived, with wit and sensuality to spare. “My affection hath an unknown bottom,” Rosalind sighs after one encounter with Orlando. The feeling is mutual.

Until July 17 (Central Park, 212-260-2400).