Recently, I had a conversation about the casting of a movie based on my books. “Jack Black!” I said. “Jack Black! Jack Black! Jack Black! Jack Black!” There was a pause on the other end of the phone, where several executives and a director were hunched over a speaker. Finally, somebody said, “The cast party would be awesome.”

“Awesome” is indeed the word for Mr. Black, as the word conveys both the grand majesty of his presence, and also, in the word’s 1980s valley-lingo connotation, the wigged-out smirk he brings to all his roles. As a comic actor, he tightropes between honesty and sarcasm and never falls: he does embarrassing things but he doesn’t embarrass the audience; he’s willing to make a fool of himself, but he never looks like a fool; and he mocks people and phenomena for whom mockery is the highest tribute. After his best work, you don’t just want to applaud—you want to wolf-whistle and hold a lighter up in the air.

After some theater work, he debuted playing a star-eyed fan in Tim Robbins’s smart, hilarious, and sadly prescient mockumentary Bob Roberts, standing creepily outside the hospital, gazing unblinkingly at his hero. In Jesus’ Son, he played a junkie you’d want to party with; in High Fidelityhe played a clerk you’d want to work with. And in his creation Tenacious D — an acoustic duo with Kyle Gass that has birthed a TV series, an album, and a stadium tour — he parties with everyone, sending up heavy metal and other 1970s rock tropes through an achingly sincere love. For years, he was a favorite on the drop-dead hilarious Mr. Show — as soon as he stepped onstage, in sweaty overalls or a biblical robe, you knew a song was coming, and coming hard. Now, he’s a bona fide movie star, with School of Rock as perfect a vehicle as one could hope for.

Mr. Black and I spoke on the phone — he was in Los Angeles, mid promotional blitz; I was in San Francisco, packing for a book tour. For reasons now unclear to me, I decided we should talk about wedding etiquette. It just seemed like the thing to do. I had an awesome time.

—Daniel Handler

DANIEL HANDLER: Have you attended a lot of weddings?

JACK BLACK: I have, unfortunately, attended a lot of weddings.

DH: Have you presided over any weddings?

JB: No.

DH: Have you been married yourself?

JB: No.

DH: Have you crashed any weddings?

JB: No. I only go when invited and usually I’m really bored. I haven’t been to many good ones.

DH: What’s the most boring part of a bad wedding?

JB:...