On Older Than My Old Man Now, his most recent (and 22nd overall) album, Loudon Wainwright III reflects — with his idiosyncratic blend of humor, pathos and great sensitivity — on life as a wide–eyed 64–year–old man.

The sometimes somber autobiographical subject matter is leavened by the guest appearances of Dame Edna Everage (on “I Remember Sex”) and Ramblin’ Jack Elliott (“Double Lifetime”). Most notably, the piss is taken with chorus vocals by Wainwright’s entire family (including his artist offspring Rufus and Martha Wainwright, and ex–wife Suzzy Roche) on a bluesy paean to middle age called “The Here & the Now”:

The strangest story ever told was how I got to be this old.

At the close of World War II, my folks did the deed that the young folks do.

In ’46, out I came — this world would never be the same!

Indeed. Wainwright cut his first album in 1970, and only ever really had one hit (the ’72 novelty song “Dead Skunk (In the Middle of the Road).” But thanks to an incisive wit, a soulful high–tenor voice and an unshakable talent for composing unforgettable songs, he has an enormous, loyal cult following.

The extended Wainwright family has given the world some of its most interesting moments. From Loudon’s breastfeeding opus “Rufus is a Tit Man” (1974) to Rufus’ “Dinner at Eight” (2003) to Martha’s ode–to–Dad “Bloody Mother Fucking Asshole” (2004), the Wainwright gang has never shied away from talking — and not always politely — about one another.

The lineage is remarkable: Loudon Wainwright Jr. was a longtime editor and columnist for Life magazine, and Rufus and Martha’s mother was singer/songwriter Kate McGarrigle. Loudon and Suzzy’s daughter Lucy Wainwright Roche is also an acclaimed singer/songwriter.

Sloan Wainwright (Loudon’s sister, aunt to Rufus, Martha and Lucy) is one of the performers at the third annual A–Town Get Down, March 2 at the Charles Morris Center.

Loudon is the headliner.

Some people might remember Wainwright from his appearances on the ‘70s TV series M*A*S*H* (as “the singing surgeon”). More recently, filmmaker Judd Apatow has turned a new generation of fans onto his music — not only has Wainwright acted and/or provided songs for The 40–Year–Old Virgin, Knocked Up and This is 40, Apatow produced a 2011 Wainwright box set retrospective called, appropriately, 40 Odd Years.

And that, they have been.

You’re 10 years older than me, but on “The Here & the Now” and “My Meds” and “Older Than My Old Man Now,” you’re almost telling my exact story. How did you do that?

Loudon Wainwright III: It’s a dirty job, Bill, but somebody has to do it. This is something that I think about a lot, and not only recently. There’s a song on the album that I wrote in 1975 with my then–wife, Kate McGarrigle, called “Over the Hill.” So when I was 28 or something I was already looking forward with some nervousness. Now that I’m at the ... advanced age that I’m at, it made sense to gather together a group of these songs and offer them up as a “theme,” so to speak.

The more recent songs are about the more specific vagaries —to use a fancy word — of getting old. The song “My Meds” is basically a list. I do that a lot. I make lists in songs.

Did you get your sense of humor from your father?

Loudon Wainwright III: I don’t know if I got it all from him, but he had a great sense of humor. In addition to the usual suspects, the Bob Dylan/Beatles/Rolling Stone triumvirate that anybody my age would listen to, I secretly loved Alan Sherman, Tom Lehr and Ray Stevens. And even Gilbert & Sullivan. Guys who wrote so–called novelty songs.

You’re known for your whimsical songs. Was that an evolution — did you start out wanting to be “the new Dylan” or were you out of the box that way?

Loudon Wainwright III: Well, my first album was a pretty serious, angsty, I’m a miserable young guy kind of a thing. But as I performed, the class clown in me came out. So on my second album is a song called “Nice Jewish Girls.” And that was kind of the beginning. I found out that I could make an audience laugh, and then swerve back and do something more serious, too. I like to think of myself as a switch hitter. Obviously not all of the songs on the album are funny; some of them are rather grim. In my show I like to make people laugh, but I like to make ‘em wince, and twitch and freak out, and cry if possible.

With you and Kate as parents, was it a foregone conclusion that your kids would be musicians?

Loudon Wainwright III: It wasn’t foregone, but the deck was genetically stacked for Rufus and Martha. And Lucy ... all three of those kids grew up with guitar cases all over the place, and banjos, pianos, and going on the road. So it’s no surprise that they wound up in the biz.

I loved Rufus’ cover of “Across the Universe.”

Loudon Wainwright III: It’s funny, I was in a restaurant last night, and that came on. I felt like I should have gotten a free glass of wine. Or maybe even a martini!

Has it been frustrating over the years to have that “Dead Skunk” footnote by your name? “Oh, it’s THAT guy.”

Loudon Wainwright III: It’s not a problem for me at this point. If you go to one of my shows, there might be a timid voice in the back saying “Dead Skunk!” And that voice usually is ignored, by the way.

There are plenty of other songs that are being called out for. It was so long ago. I mean, it was a problem for a while. I remember when I made my album after the album that had that song on it, the label said “Where’s the funny animal song?”

Why did you and Judd Apatow click?

Loudon Wainwright III: When he was a teenager growing up on Long Island, he saw me on David Letterman’s morning show and he really liked it. Later, he started to come to my shows, which of course I didn’t know. He was a teenage kid. Years later, he called and asked me to audition for his show Undeclared. I had done some acting, but I hadn’t seen (his series) Freaks and Geeks. He sent it to me, and I thought it was great.

And in the last 10 years, I’ve been in a couple of his movies. I worked with Joe Henry on the music for Knocked Up, and Rufus and I sang a song together for This is 40. So Judd has continued to use me, and I’m very grateful and happy about that.

The box set never would have happened if it hadn’t been for Judd. He literally had the power to say “Put it out. This guy needs a box set.” So it happened.

It’s that thing of, if you stick around long enough, guys who were fans of yours when they were teenagers come into positions of power!

Loudon live: "My Meds" http://www.youtube.com/watch?v=SjQG0aGozMI