WESTON, Vt.  “There are some roles I’ve gotten,” Christopher Lloyd said the other day in his gravelly, jittery, half-mumble of a voice, “that when I get the script, sometimes I ask, ‘Why me?’ It’s not that I object. It’s like, ‘What do they see in me that they want to see in this role?’ ”

Sitting in a rehearsal room at the back of a farmhouse here, hunched over a small table that will represent the kitchen of a well-known Brooklyn family, Mr. Lloyd was referring to some of the best-known roles in the coterie of cracked characters he has played in his career: Reverend Jim, the perpetually out-of-it cabby on television’s “Taxi”; Kruge, the nefarious Klingon commander of “Star Trek III: The Search for Spock”; and yes, even Dr. Emmett Brown, the excitable inventor who taught a generation of moviegoers to pronounce the word gigawatt starting with a soft g in three “Back to the Future” films. So when Mr. Lloyd was given the opportunity by a small New England theater company to play nearly any part he desired, his choice was almost as improbable as the notion of a time-traveling DeLorean sports car. He selected Willy Loman, the crumbling patriarch of Arthur Miller’s “Death of a Salesman,” whom Mr. Lloyd will portray at the Weston Playhouse in a run that begins on Thursday.

It is an epic part  arguably the canonical role of American theater  and one Mr. Lloyd knows he might never have landed were it not for family ties to the theater company and the serendipity of summer stock.

But contrary to the air of agreeable discombobulation Mr. Lloyd projects, it is an assignment he approaches with profound seriousness, knowing he might never get the chance again. “This isn’t like coming up, doing a show and going home,” he said. “Whatever deficiencies I have, or where I fall short, I know I’m giving it everything I have to give.”