On Wednesday night, David Hallberg made his debut as Romeo in American Ballet Theatre’s production of Kenneth MacMillan’s “Romeo and Juliet.” Opposite Paloma Herrera’s Juliet, it was definitely a performance worth watching.

Mr. Hallberg’s portrayal of Romeo was an extension of the dancer’s own style. In the same way that Mr. Hallberg takes pains to cleanly polish each step, his Romeo was neither hot-blooded nor hot-tempered, but rather polite and well-mannered, drawn into violent confrontations with reluctance and disdain.

Mr. Hallberg has a solid technique, but the caliber of his dancing remains uneven. He performed much better in his solos during the balcony scene — he shaped his renversés and attitude turns perfectly — than in the scissory jumps of his Act II expostulations.

Quite apart from the question of technical consistency, Mr. Hallberg has shown over the last year a significant ability to shape his muscular expression and temperament, which means that he can surprise you. As Balanchine’s Apollo earlier in ABT’s Metropolitan Opera season, for example, his legs demonstrated a suppleness that suited the role’s adoption of 1920s modern dance and musical comedy. At other times during the season, he has seemed dry to the point of brittleness — which may be because of his heavy workload — or dry in exactly the kind of ascetic key that suits the danseur noble.

Ms. Herrera’s introverted and dreamy Juliet never overpowered Mr. Hallberg. She seemed to have adopted some of the techniques for signaling the way thought precedes action that were taught at the Kirov Ballet in St. Petersburg, which was in thrall to Stanislavsky’s teachings at the time “Romeo” made its premiere there in 1940. Not simply by the expression on her face, but even more by the focus of her energy, the positions of her head and body, and the timing of her gestures, she succeeded in conveying the thoughts as well as emotions of her heroine.

Charm has never been Ms. Herrera’s ace card, but in the Act II wedding scene she succeeded in charming her audience — without looking like she was trying to do so — with her eager yet modest demeanor and mesmerized looks at Romeo. In a role that contains much walking and running, the imprint of her foot was beautifully cushioned throughout her performance. Ms. Herrera suppressed her overdrive for most of the performance, and when it fleetingly re-appeared, it served her characterization, as when she darted into Friar Laurence’s cell to ask for the potion with a velocity so high that she almost came skidding to a stop.

In the past, Mr. Hallberg has not been a sturdy partner. He has improved a great deal, but Wednesday night’s duets betrayed an element of caution, particularly during the balcony adagio, which contains some of the trickiest partnering maneuvers. Nevertheless, the couple sustained the climactic poses with security.

A lot of the caution had disappeared by the Act III bedroom adagio and the crypt duet, in which Juliet is meant to be unconscious from her potion. In the latter, Mr. Hallberg and Ms. Herrera managed to convince us that she was dead weight. In fact, Mr. Hallberg’s partnering exertions enabled him to suggest a ruggedness that contrasted to the more aesthetic character of his interpretation.

Until July 15 (Lincoln Center, 212-362-6000).