Alex Trebek fascinates America, but we don’t quite get him. He’s a game show host, but he’s not hearty or ingratiating. He’s a comedy signifier, most famously lampooned by Will Ferrell on “Saturday Night Live” for many years, but he also seems to be in on the joke. My picture of him has been built up in little glimpses over the years, to the point where I finally feel confident handling the endless stream of “What’s Alex like?”

In person, he’s decidedly not the stern, judicial presence you might expect. On TV, he’s all business. He has 61 clues to get to, and not a lot of time. Hosting such a dense, fast-moving game is an insanely hard job, but he makes it look effortless. Here’s the belief that lies at the core of Alex’s TV persona: “Jeopardy!” itself, not he, is the star of the show. It’s all about the format, the players, the facts, the dissemination of answers and questions. It’s hard to imagine any modern TV personality deftly avoiding the spotlight like that.

But when the cameras stop rolling, Alex is a looser, even goofy presence. He takes studio audience questions at every break, sometimes slipping into funny accents or even bits of soft-shoe. He still has the slight testiness, the dry imitation hauteur you can see when he spars with contestants in the interviews, but he’s gracious and candid and self-deprecating. The audience eats it up.

“And does he actually know all those answers?” I get asked. Not everyone likes that a big part of the “Jeopardy!" host’s job is to correct wrong answers — er, questions — no matter how gently Alex offers his traditional “ooh, noooo, sorry.” Of course Alex has all the responses on a big sheet of paper in front of him, but he’s also well-read and well-traveled, the kind of dad with a basement full of old National Geographics. When he pronounces the name of an Italian aria hyper-accurately, or explains that a contestant got George V and George VI confused, he’s not putting on airs. Yes, he really knows that stuff.

Carson and Cronkite are long gone, but Alex Trebek remains, the last of the old-school broadcasters who once visited us every night as a matter of ritual. When the syndicated modern “Jeopardy!” began in 1984, he was perhaps an odd choice to replace the show’s original host, the dignified Art Fleming: He was young, sexily mustached, fresh from dopey daytime game shows like “Battlestars.” But two generations of youngsters have now grown up on his clipped syllables. College students and retirees alike plan their evenings around his reassuring presence. He takes it seriously, being the face of “Jeopardy!,” the voice of facts in a post-fact world. I’ve seen him with the beaming tourists who sit in his studio audiences and the awe-struck, bookish kids for whom he was the host of the National Geographic Bee for 25 years. He knows how much he means to people, and I hope it gives him comfort that so many people are pulling for him now.