There may be some of you who hear the title King Lear and, knowing only of the play’s reputation as the mack daddy of all Shakespeare tragedies, immediately presume that any evening production of the piece will last well into the next morning. Allow me, then, to quell your fears: Saturday’s Genesius Guild staging of the Bard’s opus began promptly at eight o’clock, and after the night’s presentation had concluded, I was back in my car by 10:55.

As most will admit, however, a show’s actual length doesn’t matter nearly as much as how long a show feels. Yet thanks to smart pacing and judicious script editing, director Michael King’s King Lear moves along at a terrifically agreeable clip. The stage action is impressively timed but rarely feels rushed – leaping on their entrance cues, actors appear for new scenes before castmates from the previous scenes have fully exited the stage – and most of the performers’ readings on Saturday were delivered speedily but without losing the meaning of Shakespeare’s words, which can’t be the easiest of tasks.

I doubt it’ll offend the other 26 members of Lear’s ensemble to say that no one proves more adept at maintaining both speed and meaning than Lear himself, as Pat Flaherty gives one of those beautifully expansive, achingly soulful performances that might be the reason God invented theatre. With Flaherty’s vocal timbre rising to higher and higher peaks of anguish, and his collapsing physicality mirroring the deterioration of his monarch’s mind, Lear’s emotional arc from wrathful anger to full-scale madness is harrowing in the most exciting way. Flaherty, however, is also savvy enough (and, blessedly, enough of a natural comedian) to know when a lighter touch is required.

During those occasions when he’s allowed to be funny, Flaherty earns deserved laughs with his childlike innocence – in a wonderfully quick aside, the barefooted Lear asks for assistance in removing his boots – and the actor demonstrates the proper faith in Shakespeare’s text to know that he doesn’t have to push for his effects. Even the king’s most recognizably Great of great lines (“How sharper than a serpent’s tooth it is to have an ungrateful child,” “Never, never, never, never, never”) are delivered with masterful simplicity. In short, Flaherty is a wholly satisfying evening of entertainment unto himself. And when you throw in co-star Todd Schwartz’s topnotch sound design, Ellen Dixon’s stellar costumes, a handful of additionally excellent portrayals, a bunch of nicely committed ones, and, for an opening night, a noticeable absence of dialogue flubs, the total experience of Genesius Guild’s Lear, for me, didn’t feel like (almost) three hours. Only the first scene felt like three hours.

Actors, I’d argue, are rather like vampires: They tend to be less lively in light than in darkness. So aside from the understandably stagnant stage composition in the protracted intro – in which Lear divvies up his estate between the two daughters who feign to love him and disinherits the daughter who does – maybe we can chalk up Saturday’s underwhelming opener to the sun (and the heat). Still, beyond Flaherty’s Lear, Schwartz’s focused and direct Kent, and Lauren VanSpeybroeck’s inspiringly naturalistic Cordelia, there was too little going on in the faces of the other dozen-plus amassed on stage. Those who spoke appeared to briefly wake up for their dialogue, but when their lines ended, they receded to a state of near-complete disengagement, making the paucity of stage movement in this lengthy passage even more apparent. Deadpan expressions are perfectly fitting for Lear’s first scene – we should discover the characters’ allegiances, or lack thereof, gradually – but there’s a huge difference between blank looks with obvious thought and intent behind them and looks that are just blank. (If only Shakespeare had written the king’s Fool, played here by James Alt, into the opener; cajoling, riffing, tumbling, and, at one point, mooning the audience, Alt is a magnificently inventive, happy presence.)

But stick with the show, because after its prelude ends – and, coincidentally or not, the sun begins to set – you’ll realize you’re in very good hands, and not just those belonging to Flaherty and King. Both Schwartz and VanSpeybroeck are exceedingly fine throughout, and they’re eventually matched by Kitty Israel’s Goneril, with her smashingly vindictive wickedness, and Tyler Henning’s Edgar, whose nearly naked, twitchy-madman guise is a robust piece of physical acting. There are touching, gracefully elocuted portrayals by Earl Strupp and Bryan Woods, and enjoyably outsize, untrustworthy ones by David Cabassa and Alaina Pascarella, and several confident turns and bits of outré business that Lincoln Park’s crowd was alive to. (Michael Callahan’s blinding of Strupp was memorably vicious, and Andy Curtiss, obviously having a blast as the steward Oswald, reaffirmed that swishy stereotypes, for better and worse, are comedic money in the bank.) Pat Flaherty makes Genesius Guild’s King Lear unmissable, but it’s still wonderful to know that whenever he’s off-stage, there are plenty of reasons not to miss him.

For information, visit Genesius.org.