As his new album’s title relates, Loudon Wainwright III is Older Than My Old Man Now — his old man, of course, being the late Loudon Wainwright, Jr., the esteemed Life Magazine columnist and senior editor.

“Singer-songwriter contemporaries of mine have recently taken to writing memoirs and autobiographies,” notes Wainwright. “I decided I would try to tell the story of my swinging life in a three and one-half minute song.”

He’s speaking specifically of the album’s lead track “The Here & the Now,” which features jazz guitar great John Scofield and backing vocals from all four of Wainwright’s children — Rufus and Martha Wainwright, Lucy Wainwright Roche and Lexie Kelly Wainwright — as well as two of the three moms, Suzzy Roche and Ritamarie Kelly. But the album as a whole reflects the stage he’s reached in his life, and as he so wryly puts it, the “death ‘n’ decay” that inevitably accompanies it.

One track which cuts directly to the issue, “The Days That We Die,” remarkably brings together three generations of Wainwright males.

“My Dad wrote the recitation, and I’m singing with No. 1 son Rufus,” says Wainwright. “That’s my grandson Arcangelo Albetta — Martha’s kid — I’m walking with on the beach photo that’s part of the CD artwork. Not only that, but Loudon Wainwright I is referenced in the title track, so in fact there are five generations represented on the album!”

Wainwright’s father, who died in 1988, also wrote the recitation that introduces the album’s title track. “Please believe me when I say that collaborating with my long gone progenitor at this late date felt pretty damn big,” says his son, who also lifted the opening line of “Double Lifetime” from one of the notebooks that his father used to carry around with him to write in.

Another key family member who is no longer living, Wainwright’s ex-wife Kate McGarrigle (the mother of Rufus and Martha), is represented by “Over The Hill” — “the one song we wrote together, way back in 1975.” Martha Wainwright accompanies her father vocally on the track, as does multi-instrumentalist/vocalist Chaim Tannenbaum, his “musical sidekick and sounding board” for over 40 years. Suzzy Roche returns to sing on “10,” and even Wainwright’s lab/pit/chow mix Harry, who’s been featured (in the lyrics) in a number of his songs in the last few years, appears on “Ghost Blues” and the bonus download track for the album “No Tomorrow.”

But Older Than My Old Man Now, which was produced by Dick Connette (producer of Wainwright’s 2009 Grammy-winning High Wide & Handsome: The Charlie Poole Project), boasts stellar participants other than family.

“One voice singing a lot about death ‘n’ decay can be a bit wearing so Dick and I brought in other singers to help with the heavy lifting,” says Wainwright. “The venerable Chris Smither testifies with me on ‘Somebody Else,’ for which High Wide & Handsome alum Rob Moose wrote the string arrangement. Barry Humphries, a.k.a. Dame Edna Everage, does a duet with me on ‘I Remember Sex.’ He and I were romantically linked in two episodes of Ally McBeal a few years back, and I’ve been besotted ever since. There is no greater living and performing legend than Barry Humphries, for my money. And he’s even older than I am!”

Older than Wainwright, too, was another personal hero who guests on Older Than My Old Man Now — folk music legend and 2 time Grammy winner Ramblin’ Jack Elliott.

“After making pilgrimages to Jack’s shows for half a century now, for me to sing and play with him on an album was nothing short of a dream come true,” he says, referring to “Double Lifetime.” “Recording this song with him — perhaps my foremost musical father figure — was a gas.”

One other old friend is noteworthy: Robin Morton, a founding member of legendary Celtic group the Boys of the Lough.

“We’ve known each other since the early 1970s when we were young hell raising/up-chucking Turks on the folk music scene together,” recalls Wainwright. “It was great fun to begin recording Older Than back in May at Robin’s studio in the tiny Scottish village of Temple — just a wee bit south of Edinburgh.”

And from High Wide & Handsome also came the likes of guitar and banjo player Matt Munisteri, cellist Erik Friedlander, pianist Paul Asaro and bassist Tim Luntzel. Together, the new album’s personnel create song treatments ranging from basic guitar-and-vocal to sophisticated string settings — together with some swinging funk provided by Scofield.

Loudon Wainwright III came to fame when “Dead Skunk” became a Top 20 hit in 1972. Born in Chapel Hill, N.C. in 1946, he had studied acting at Carnegie-Mellon University, but dropped out to partake in the Summer of Love in San Francisco.

He wrote his first song in 1968, “Edgar” (about a lobsterman in Rhode Island) and was soon signed to Atlantic Records by Nesuhi Ertegun. Clive Davis lured him to Columbia Records — which released “Dead Skunk.” His recording career now consists of 25 albums, also including last year’s five-disc retrospective 40 Odd Years and his most recent studio album 10 Songs For The New Depression (2010).

Wainwright’s songs have been recorded by Johnny Cash, Earl Scruggs, Kate & Anna McGarrigle, Rufus Wainwright, and Mose Allison, among others. He has collaborated with songwriter/producer Joe Henry on the music for Judd Apatow’s hit movie Knocked Up, written music for the British theatrical adaptation of the Carl Hiaasen novel Lucky You, and composed topical songs for NPR’s Morning Edition and All Things Considered and ABC’s Nightline.

Also an accomplished actor, Wainwright has appeared in films directed by Martin Scorsese, Hal Ashby, Christopher Guest, Tim Burton, Cameron Crowe, and Judd Apatow. He has also starred on TV in M.A.S.H. and Undeclared, and on Broadway in Pump Boys and Dinettes.