Hee Seo in Swan Lake. (Gene Schiavone)

“Swan Lake,” the most iconic ballet, is forever in development. With no single standard for the ballet, no complete written record representing the original intention, it is best understood as an evolving work of art.

It’s difficult to pin down what’s “original” in this ballet. The 1895 premiere by Marius Petipa and Lev Ivanov in St. Petersburg, considered by most to be the authentic “Swan Lake,” was at the time only the latest effort to accomplish in dance what Tchaikovsky had achieved 20 years before with his dramatic, deeply layered music. Our knowledge of that production is incomplete. And other “Swan Lakes” emerged soon after the Petipa-Ivanov one, with new variations better suited to the dancers at hand.

And so it goes — and so it endures. The changeable, unfinished nature of “Swan Lake” is its greatest strength, because it allows successive artists to offer new insights into a ballet we thought we knew. This was Hee Seo’s achievement Wednesday night at the opening of American Ballet Theatre’s engagement at the Kennedy Center Opera House.

Seo, the company’s reigning ballerina, possesses many obvious and exquisite ballerina traits: long, lean limbs, beautifully pliant feet, a weightlessness that is warm rather than skeletal. But what makes her special are subtler qualities, chief among them her calm command. 

This production, choreographed by ABT Artistic Director Kevin McKenzie, has a rushed feel, with a brisk musical tempo, one intermission rather than the customary two, and a compressed ending. Yet there is no rush when Seo holds the spotlight. You can believe time pauses for her. As Odette, the bewitched princess whom Siegfried (Cory Stearns) discovers while sighting his crossbow, Seo slightly lags the beat, and makes an art of slowing everything down. This allows us to notice the fine details, such as the liquid movement of her arms, and even the fall of her fingers. Stearns, a stalwart partner, matched her understated tone and together their moonlit duet was as moving as it was deeply musical.

Reappearing as Odile, the predatory double who tricks Siegfried into betraying Odette, Seo retained her elegant command while also demonstrating thrilling creativity, as she found a new moment in which to reveal Odile’s cruelty. After she seduces Stearns in a luscious waltz, Stearns kneels and buries his face in her hands, overcome with ardor. Yet Seo wasn’t finished. She lifted Stearns’s chin, bent over him and looked him long and full in the face with a wide smile. She was savoring her triumph — you could almost hear her purr. And as the couple rose to acknowledge the applause, she gave him another pointed look — still Odile, still bloodthirsty — and laughed.

I’ve never seen a ballerina mingle beauty and cruelty so well.

American Ballet Theatre performs “Swan Lake” through Sunday at the Kennedy Center. All performances are sold out. 202-467-4600 or visit kennedy-center.org.