Loudon Wainwright 3rd is apologizing, and it’s kind of funny. Midway through the conversation, an observation about his positive mental outlook comes up. He can’t help himself.

“I hate to be such an optimistic guy,” he musters. “But it’s early in the day. Call me later, and we can see how I am.”

There’s a pause. And a confession. Even leaning into the curmudgeonly, he can’t tell a lie.

“Yes, okay, generally I am optimistic,” he admits.

Wainwright, 70, has been writing songs, tapping his generation’s malaise, doubts and fragility since dropping out of Carnegie Tech’s drama school in the late 1960s. On Thursday, July 6, he will perform at the Old Whaling Church in Edgartown as part of the Martha’s Vineyard Concert Series.

Wainwright has built an eclectic career that also includes acting; for television (M*A*S*H, Ally McBeal and Parks & Recreation), film (Judd Apatow’s 40 Year Old Virgin, Tim Burton’s Big Fish, Cameron Crowe’s Elizabethtown), and a one-man stage show called Surviving Twin. The one-man show was a collaboration with his deceased father, vis-à-vis his father’s celebrated columns for Life Magazine.

“I hadn’t read most of the columns until five years ago, when I read them all. He really was a fine writer,” Wainwright says. “The pieces in that show are the personal ones; they’re the ones that interest me because, obviously, I was there. I call this a posthumous collaboration — and we’re getting along really well.”

Like so many young people in the tumultuous 1960s, his relationship with his father was difficult. “I’ve written a lot of songs about him, and me, and us, and it. It’s great song fodder, because it’s complicated, and it’s real.”

Wainwright is also about to release a memoir, arriving Sept. 5, called Liner Notes, the subtitle of which is Parents & Children, Exes & Excess, Death & Decay, & A Few of My Other Favorite Things. It’s a book about music and family, both of which are in his blood, literally. He is the father of three well-regarded singer/songwriters — Rufus Wainwright, Martha Wainwright (their mother the late Kate McGarrigle) and Lucy Wainwright Roche (her mother is Suzzy Roche).

Wainwright’s songs — whether the poignantly vulnerable road sex invitation Motel Blues, the aching missed moment Five Years Old or the wry Bell Bottom Pants — have always been driven in part by the particulars of time, place and detail.

Musician, actor, writer, playwright — it's been a long, eclectic journey. — Hugh Brown

“I was just writing songs,” he demurs. “If they have an effect, that’s great. But I didn’t consider it a mission or a calling to change people’s lives. My first album was about what happened to me. My 27th album is what happened to me.”

If there’s a difference between writing a book and songwriting it is the amount of commitment the extended narrative requires, he says.

“I’m always just working on the next song. There’s something mysterious about the process. You can’t chase it or expect it. It doesn’t work that way. I’ll pick up the guitar and fiddle with it, and I carry a notebook around with me if something occurs to me. But I don’t sharpen pencils from 11 to 2 in a room with a legal pad to create things. In the case of a book, you get up every day, and you do it. You don’t dawdle. You don’t procrastinate. It’s the only way to get it done, because it’s a lot of work, and it really requires you do it. But the process was really interesting...I had a difficult relationship with my Dad, and I write a lot about it in the book.”

Beyond being electrified by Bob Dylan at the Newport Folk Festival, Wainwright’s influences are grounded in folk and his father.

“I played a lot of folk festivals, and some of my influences were Pete Seeger and Ramblin’ Jack Elliott,” he says. “But then I also had my father’s record collection, all those jazz and Broadway shows. Noel Coward, Frank Loesser, Rodgers & Hammerstein, who were really the best of the best American songwriters.”

For a man who believes his vast, eclectic career has evolved “song by song, and show by show,” he’s grown over time. Some songs have evolved and some have passed their shelf life. But the artist remains as vital as ever.

“I’m aware I’ve changed. I’ve gotten older, and things are different. It’s changed how I see things, but also the keys. I was playing Me and My Friend The Cat this morning, and my voice was probably an octave and a half higher than when I recorded it on my second album. Some [songs] I don’t relate to, and I don’t do them.

“When I get to Martha’s Vineyard, it’ll be 75 or 90 minutes that I am putting together for that moment. I think of it in that way. What songs shall I play? The chords I strike? What socks shall I wear? It all goes into it. But for me, those are the things I focus on in the moment. For the last 45, almost 50 years, this is what I’ve done, had my head down, working on what’s before me.”

Given its novelty, Wainwright has eschewed his song Dead Skunk (in the Middle of the Road) for years. “Now I will bring it out on occasion, because it is what it is, a fine three chord novelty song that paid for a lot of child support.”

After being told about the ubiquity of roadkill skunks on the Vineyard’s two lane blacktops, he laughs. Perhaps the occasion will present itself after all.

If not a global supernova, Loudon Wainwright 3rd created a career that’s taken him around the world, and a life filled with love and its inherent conflict, children and grandchildren, losing parents and finding a way to turn it all into art. He’s composed songs for films, television and NPR, acted for the world’s best directors and created a hybrid play that’s been staged from Los Angeles to London. And he’s still going.

“My dream was to be in show biz when I was a seven year old in my bedroom,” he says. “And it came true. I couldn’t have imagined this then, but I got what I wanted. I sure did.”

Loudon Wainwright 3rd performs at the Old Whaling Church in Edgartown at 8 p.m. on Thursday, July 6. For tickets and information, visit mvconcertseries.com.