Dubbing himself "the party captain of the holidays," Robert Earl Keen figures he's feeling pretty jolly this year.

"You know, it comes and it goes," reflects the Houston-born singer-songwriter, who will turn 59 next month. "Sometimes I feel kind of overwhelmed. I think that might be in all of our natures. This year I'm having a great time. I feel real peace on Earth, goodwill towards men. And women."

Whether he was joking or not (it's a little hard to tell), when we reached Keen by phone a couple of weeks ago, he said he was "just sobering up." He was in the early stages of the "Merry Christmas From the Family" tour, his annual trek built around the song that affectionately if sarcastically celebrates those trailer-dwelling, Salem Light-puffing, fake-snow-spewing Christmas lovers from coast to coast.

"These Christmas shows, they take a lot out of you, so you have to put a lot back in," Keen says by way of hair-of-the-dog advice.

It's not hard to see why. "Merry Christmas" is celebrating its 20th anniversary this year as something like a mantra for many folks who wear cowboy boots with their Christmas sweaters, but it came to life as just another song. It originally appears on Keen's 1994 album Gringo Honeymoon, nestled alongside other future catalog chestnuts such as "Dreadful Selfish Crime," "I'm Comin' Home" and the title tune. According to Keen, at the time he was just trying to finish the album, which was released in August 1994.

"It was around this time of year and I thought that I was making some pretty good progress," he recalls. "I realized that it was Christmas and everything comes to a screeching halt and you have to run out there and pay attention and move around, go to somebody else's house and do all the stuff with the holidays.

"The holidays are about celebration, but there's also a certain demanding element to it," Keen continues. "I was totally frustrated with that fact because I felt like I was down to the wire about writing these songs. So I sat down and I wrote I knew, what I had experienced. I had never thought in terms of being that open with my own life."

A songwriter whose vivid language and character-rich songs have sparked comparisons to both Larry and James McMurtry (whose "Levelland" Keen covered on 1997 LP Picnic), Keen admits his songs possess "a certain memoir-esque quality, if that be a word at all, but in general a lot of times they're shrouded in a certain amount of fiction or color." All that went out the window with "Merry Christmas," though.

"This one was extremely real," says Keen. "As a matter of fact, when I wrote it, I was shocked that my mom didn't have a better sense of humor. She called up my uncle Joe and said, 'Robert's written the most awful song, Uncle Joe, it's just terrible. What are we going to do?'

"He said, 'Just calm down, Juanita, it's going to be OK,' Keen continues. 'She went to her grave, I think, never telling me that she thought it was terrible, but I know now that she did think it was terrible. She thought I was I was being mean or something, but it certainly wasn't about being mean."

According to Keen, it took a good 18 months for him to realize he had an unlikely holiday hit on his hands. Furthermore — and we hate to burst the bubble of any readers who think this is strictly a Lone Star carol — but it took a couple of non-Texans to make "Merry Christmas" a full-blown phenomenon. That would be John Boy and Billy, a couple of DJs in Charlotte, N.C., who host a syndicated program with some 10 million listeners. Keen still drops in on them every so often, just like Santa Claus.

"They stumbled on it on their own; some friend of them sent it to 'em," says the singer. "They loved it, and they played it three times a day in their drive-time morning show. All of a sudden they're calling me up and putting me on the show, and we're coming in the studio. We've been friends ever since."

By the way, Keen's career beyond his Yuletide hit is doing just fine, thanks. In February he'll scratch a longstanding itch and release his first-ever all-bluegrass album, Happy Prisoner: The Bluegrass Sessions; more on that in a month or two. But this time of year "Merry Christmas" has completely swallowed his stage show — the production design includes a stage resembling a Christmas-tree lot, strewn with accessories like packs of cigarettes and even boxes of tampons. This year's theme is the 1970s, and Keen says "we welcome everybody thinking in terms of being in the '70s and wearing bell bottoms and Fu Manchu moustaches, things like that."

Keen has one more present to put in fans' stockings this year, too. For his past few holiday tours, his band — guitarist/string savant Rich Brotherton, bassist Bill Whitbeck, steel guitarist Marty Muse, and drummer Tom Van Schaik — has come out early for a brief set of Christmas songs of their choosing; Keen used to ask that they dress in all-black and open the show with "'Greensleeves' and English madrigals."

That tradition has evolved into Santa Is Real, a brand-new album of jazzy Christmas tunes played '40s/'50s swing-style, including a couple from Vince Guaraldi's Charlie Brown Christmas soundtrack. Credited to "The Xmas Men," the title winks at the Louvin Brothers' classic 1959 album Satan Is Real, and Keen was only too happy to foot the bill.

"For a truly homemade project, it's phenomenal," he crows. "There's phenomenal stuff going on all the time in our lives all around us, and in this situation these guys got together and made a really cool, great fun, happy-sounding Christmas record, and they did it all by themselves."

At this point "Merry Christmas From the Family" is universal, so much so that it stays in Keen's set year-round. At his most recent Houston show last September, opening for old Texas A&M buddy Lyle Lovett, Keen introduced his Uncle Joe in the audience and revealed his role in the song's creation. ("He's part of my kin that really can't figure out how he's kin to me," the singer explains today.) Still, there's just something about hearing "Merry Christmas" during the holidays that makes it glow a little brighter. Or it could just be that extra glass of egg nog talking.

"It became one of those things where I'd start strumming the first two chords and people would start screaming and yelling," Keen says. "It always felt good. It's easy to play. One of the magical things about it is that it's so slow that I think anybody that can even barely play the guitar can play it."

Robert Earl Keen's Christmas Spectacular, with special guests the X-Mas Men and special guests Dawn & Hawkes, returns to House of Blues this Friday, December 26. Doors open at 7 p.m.