Steve McLain could have named his new downtown restaurant after himself. With a success like ¡Oba!, which celebrated its seventh birthday on Halloween, he’s earned that right. Instead he named his 8,700-square-foot, $2.5 million Fox Tower showcase after his 4-year-old son, hoping to infuse diners with the childlike enthusiasm that little Harrison has brought into his own home.

Although modeled after the aesthetic of the family room of the McLain home in King’s Heights, the dining room at Harrison, with cherry wainscoting and artwork from the Alysia Duckler Gallery, feels like the penthouse of a Park Avenue socialite. Even situated as it is just yards above street level, Harrison somehow conjures the memory of New York’s lost culinary showplace, Windows on the World, as it draws hungry, haberdashered hordes fresh from the Keller and the Schnitz. The insulated, clean and unhurried vibe transports patrons not so much up in altitude as back through time, to an optimistic era when dinner meant securing a power table, savoring hushed conversations over another round of Manhattans, and treating friends to an unbounded session of after-theater excess.

In the face of a wine list long enough to require Cliffs Notes, the cocktail menu looks more manageable, and it proves both inspired and tempting. Amid samplings of “old school” and “new school” creations such as the His Manhattan (McLain’s favorite, made with Woodford bourbon) and the Sage White (white cranberry juice and Danska grapefruit vodka with a fresh sage leaf), an evening at Harrison can quickly evolve into an all-night adventure, every bit as spirited as the monkeyshines of a wide-eyed little boy.