Charlie Baker is dull. He’s depressing. He’s shy. He hates to speak and hates even more to be spoken to. He has the personality of Sheetrock. Just ask his wife. She’s the type of spouse that puts the “extra” in the term extramarital affair. Last count, she was up to 23.

What’s a guy like Charlie to do?

In Larry Shue’s kooky comedy “The Foreigner,” which opened over the weekend at Penobscot Theatre, Charlie gets into some heavy-duty role playing, and finds a side of himself that is, to put it mildly, exciting.

Of course, he doesn’t mean to find himself. But when his Brit friend Froggy takes him to a fishing lodge in Georgia for the weekend, introduces him as a foreigner who can’t speak English, and then leaves him there, Charlie finds out what it’s like to be a stranger in a strange land. And he loves it.

But he gets into some trouble when he overhears some big, dangerous secrets that others don’t think he can understand. So not only does Charlie have to NOT respond to what he hears, he has to figure out how TO respond to what he hears so that he can save both the lodge and some lives. The responsibility requires him to be clever and inventive, and he finds that he has what it takes to be not only a great guy but a hero.

Although the program notes written by director Jay H. Skriletz may leave you feeling a bit like a foreigner in your own language, his production will not. This is situational comedy, and Skriletz plays it up at every turn.

Thus, it was only natural to cast funny man Robert Libbey as Charlie. Libbey’s most elegant strength is comedy, and this role showcases that skill. He gets the audience laughing and keeps the pitch high for nearly 2 1/2 hours. It’s his show, and that point is driven home again and again, right to the end when he makes a most prodigious entrance for his curtain call. The focus on him dribbles into overstatement in that last moment, but the audience members don’t mind. By the end of the show, he has made Charlie their hero, too.

The rest of the cast quite ably carries out its duties. The strongest among them is Davidson Kane, who plays a redneck bad boy with an itch to snuff foreigners of any kind. Ruth Miller, as the lodge owner Betty, whips up some down-home humor of her own and is very amusing. Ron Adams is smashingly simple-minded as Ellard, a half-wit boy who helps save the day. These three do the hard and laudable job of effectively — and hilariously — creating the atmosphere of the South.

Shaun Dowd is jaunty and quick-witted as Froggy. Neither Ron Lisnet, as a conniving reverend, nor Jennifer Monahan, as his deb-trained fiancee, are as dynamic as they might be in these terrifically typical roles, but that doesn’t hold the show back from being a laugh a minute.

Newcomer Mark D. Nutt has designed a set that looks authentically like a rugged fisherman’s spot — plus it’s sturdy and dependable. In addition to constructing a lush outdoorsy background, he has rigged up a rainstorm that blows through the front door. It’s an impressive bit of engineering. And not the only special-effect trick he has up his sleeve for this show.

Larry Shue’s script is solid sitcom entertainment — complete with outrageously sexist jokes and a ludicrous outcome with all sorts of alarming implications about how to get along with people. But this is good ol’ American humor, and you’re not really meant to do anything other than laugh your head off, which you will if you go see “The Foreigner.”

“The Foreigner” will be performed 7 p.m. Thursday, 8 p.m. Friday, 5 and 8:30 p.m. Saturday, and 2 p.m. Sunday through April 14 at the Penobscot Theatre. For tickets, call 942-3333.