Francesca Faridany, with Ted Koch, gives a riveting performance as heroine Nina Leeds in Shakespeare Theatre Company’s production of Eugene O’Neill’s “Strange Interlude.” (Scott Suchman/Courtesy of Shakespeare Theatre Company)

About two hours into Shakespeare Theatre Company’s 3-hour, 45-minute production of “Strange Interlude,” the tragic condition of Eugene O’Neill’s troubled, meddlesome heroine, Nina Leeds, comes securely into focus. And the laughter in Sidney Harman Hall begins to build.

The chuckles start sporadically, as the audience senses ever more confidently the humor in the contradictions between what the characters say and what they really think; in this Pulitzer Prize-winning 1928 play — rarely revived on American stages — O’Neill had the audacious idea of requiring the nine characters to give voice, in audience asides, to all of their private thoughts.

As the guffaws multiply on this curious though by no means uninteresting evening (thanks in part to a riveting central performance by Francesca Faridany) one is compelled to wonder: Is this O’Neill, probing a tormented soul, or Noel Coward, exercising a delicious wit?

What seems to account for this strange phenomenon is the distance the popular mind has traveled since the restless O’Neill heaved one theatrical experiment after another into the field of vision of American culture. “Strange Interlude” — originally a more than five-hour play, complete with dinner break — has so many melodramatic plot twists that a discussion of them would fill the pages of an issue of Soap Opera Digest. As the characters reveal for us their takes on each juicy, dirty secret, and then in the next instant decisively betray a lover, embroider a lie, or execute a 180-degree shift in behavior, the jarring, even ludicrous, pivots strike many a contemporary theatergoer as risible.

In director Michael Kahn’s brisk and handsomely pared-down production, I could not tell all the time whether the laughs the actors generated were intentional; while the contortions that O’Neill puts his characters through are now the raw material for sketches on “Saturday Night Live,” the characters themselves are not. Nina, in particular, spends the quarter-century that “Strange Interlude” examines trying to rebound from the death in World War I of the great love of her life, the unseen Gordon. At the start of the evening, the aerial tailspin flashing in vintage black-and-white footage on the bare walls of Walt Spangler’s admirably spare, epic-scale set is a visual cue for the emotional one that colors all of the play’s ensuing anguish.

But even if O’Neill’s antique construct contributes to some miscommunication of tone, the piece as a whole stands as a watchable milestone in the development of modern American drama. Yes, the rewards are felt only marginally in the slow early movements of this three-act, two-intermission mini­marathon, which Kahn — whose O’Neill productions include a well-remembered revival of “Mourning Becomes Electra” in 1997 — has expertly trimmed. So if you hang on (and, admittedly, more than a few chose not to on Monday night, in a far-less-than-sold-out Harman Hall), the characters’ endless wrestling with the truth, their self-serving ruses and self-protective gambits, will jell for you into something surprisingly absorbing.

Kahn goes out on a limb with this offering, a labor of love for sure; it qualifies on no level as a repeat of “Tamburlaine,” the bloated spectacle with which he opened Harman Hall, back in 2007. O’Neill partisans and other drama diehards should vote for this kind of nervy programming with their wallets; the production is by far the most adventurous entry in the spring’s Eugene O’Neill Festival, whose other main events are Arena Stage’s productions of “Ah, Wilderness!,” which is closing Sunday, and “Long Day’s Journey Into Night,” which officially opens later this week.

The structure of “Strange Interlude” suggests there are as many plays unfolding on a stage as there are characters. From the entrance of the first character, Robert Stanton’s thwarted Charles Marsden — as psychologically entangled with Nina as virtually every other male character in the play — we get soliloquies lengthy and clipped about the state of a character’s mind, or about what he or she supposes is going on in the mind of another’s. Some of it is wry: “The professor of dead languages is talking again,” Faridany’s Nina murmurs acidly to herself about her father (Ted van Griethuysen). And some of it sounds ridiculous: “I can give myself without repulsion,” she remarks about the loser-turned-millionaire (Ted Koch) she’s married, for reasons only a playwright would understand.

As transparently as psyches are exposed, however, and no matter how cleverly the manipulative Nina tries to bend others to her will, she remains tethered to a mournful past and the cataclysm that transformed her. That tragedy adds dramatic weight to “Interlude,” even if, for long stretches, it can’t escape the encumbrances of melodrama. Still, it’s a melodrama churning with invention.

Kahn’s cast, outfitted splendidly by costume designer Jane Greenwood, boasts two portrayals of outsize impact, just the variety required in this protracted show. Faridany, who played Rosalind in the company’s mad fumble of “As You Like It” in 2009, turns in a majestic performance here. Giving the patrician Nina a soigne accent akin to Katharine Hepburn’s, Faridany presides with an enthralling hauteur over the men eternally swooning for Nina, including the handsome doctor Ned (Baylen Thomas), who abandons medicine in hopes of getting her out of his mind. (He fails.) If O’Neill did indeed consider that “Interlude” provided his most detailed portrait of a woman, then for him, complexity in a female character meant a conniving, vain and utterly deceptive character.

Faridany’s worthy match is Stanton, whose Charlie makes up in dyspeptic durability what he lacks in virility; the performance grows comically riper as the years fly by and Charlie stews more bitterly in his own vinegar. (The years’ passing aren’t recorded quite so convincingly in the robust visages of Thomas and Koch.) Van Griethuysen and Tana Hicken contribute resonantly in vivid, one-scene roles, and Rachel Spencer Hewitt locates the right kind of sauciness in the part of Nina’s daughter-in-law-to-be. Even with its many narrative bumps, the intriguing bruises raised by the characters of Kahn’s “Interlude” ultimately make it worth the luxurious time investment.

Strange Interlude

By Eugene O’Neill. Directed by Michael Kahn. Lighting, Stephen Strawbridge; composer and sound, Fitz Patton; projections, Aaron Rhyne; wigs and hair, Tom Watson; literary associate, Drew Lichtenberg. With Joe Short, Jake Land. About 3 hours 45 minutes. Through April 29 at Sidney Harman Hall, 610 F St. NW. Call 202-547-1122 or visit