‘I knew that Elmo should represent love’

“Being Elmo,’’ Constance Marks’s impossibly sweet documentary on the indefatigable puppeteer who gave “Sesame Street’’ a second lease on life, opens locally at the Brattle and Coolidge Corner theaters Wednesday. Clash rescued Elmo, the little red monster, from the show’s dustbin more than a quarter-century ago, reimagining the neglected, gruff-voiced Jim Henson creation as a huggable, high-pitched companion who has since enthralled millions of children across the globe.

“I knew that Elmo should represent love,’’ says Clash in the film. Such a statement might have been cloying if not for his genuine love of craft, coupled with his matter-of-fact personality and occasional glimpses into his wry sense of humor.

Marks, who previously made films on social issues such as homelessness and addiction recovery, learned her own craft as an assistant editor for the Maysles brothers, David and Albert, the Boston natives who helped shape cinema verite. When she began working on “Being Elmo,’’ she did what most documentarians do: She looked for the conflict.

But Clash, a shy youngster from a low-income section of Baltimore, had surprisingly little in the way of obstacles en route to becoming one of the world’s most famous puppeteers. By age 19, he was already working on “Captain Kangaroo,’’ which was the number one children’s show on television for much of its long run. Shortly thereafter he moved to “Sesame Street,’’ where he joined a cast headed by his idol, the late Muppets creator Henson. When he remade the fuzzy red puppet called Elmo as a precocious preschooler who speaks with helium in his voice in the third person (“Elmo loves you!’’), the character - already a failed experiment for several “Sesame Street’’ puppeteers - became an overnight sensation.

“I would say to Kevin things like, ‘What kinds of barriers or challenges did you have as a kid?’ ’’ Marks recalled during a visit to Massachusetts back in April. He had them, she said, “but they were, like, where to get the right fabric [for the puppets he was building].’’ She was sitting with Clash and her husband, James Miller, an Emmy Award-winning cameraman whose work on “Sesame Street’’ first introduced the filmmaker to her subject. While their film screened for a packed, enthusiastic house on opening night of the Independent Film Festival at the Somerville Theatre, the trio relaxed in a modern office space two floors above.

Clash, sprawled in an overstuffed armchair and looking ready for an early evening nap, said he kept an insane schedule when he was first starting out in New York. Working under the wing of the late Kermit Love (the Muppet builder who designed Big Bird), Clash spent mornings on the “Captain Kangaroo’’ set, afternoons making another children’s show called “The Great Space Coaster,’’ and nights recording songs for that show. Then he would stay up until 5 or 6 in the morning building new puppets for the Captain. The pace was grueling. “I remember having a minor breakdown back in Baltimore,’’ he said. But he was fulfilling his boyhood dream.

In more than three decades of altering his voice and performing on his knees, manipulating bits of cardboard and yarn, Clash, 51, has not slowed. His biggest regret, as he admits in the film, is the fact that he was often unavailable to his daughter, Shannon, the sole child from his one marriage. He thought long and hard about telling that side of his story on camera, he said, ultimately deciding it might help the family-friendly movie make a connection.

“It’s a different day and age,’’ he said. “Everybody’s working now, so I thought: This is something you can play to.’’

But despite his self-criticism, Clash works at being a father. He was on the cellphone with Shannon as the interview got underway, and when he hung up he mentioned that he would miss an upcoming “Sesame Street’’ gala to attend her high school graduation. Clash is amazed at how responsible his teenage daughter has grown. When he took her out for driving lessons, he said, she drove so slowly “she couldn’t even get over the speed bump.’’ The recollection triggered a big, rumbling laugh.

Shannon was making plans to begin her studies at the University of Maryland at College Park - the same school Jim Henson attended, her father noted with obvious pride. Henson, the Muppet creator who died in 1990 at 53, was Clash’s mentor and, for the last few years of his life, friend. Clash would love to follow in the icon’s ambitious footsteps, directing feature films like Henson’s “The Dark Crystal’’ and “Labyrinth,’’ not necessarily for children.

Though Henson grew up an avid fan of Burr Tillstrom, the man behind the early TV puppets “Kukla, Fran and Ollie,’’ he had few conversations with Clash about the history of the form. “Jim was not a storyteller,’’ said Clash. “He liked to get down and say, ‘Let’s make each other laugh.’ ’’

For parents who barely survived their kids’ Elmo infatuation and have a momentary surge in blood pressure when they hear the “Elmo’s World’’ theme, let it be said that the scenes in “Being Elmo’’ in which Clash and his red puppet meet their admirers are guaranteed to melt your heart. When they see him in person, very few children are skeptical about the puppet-puppeteer relationship, he said.

“They grew up watching these characters. They’re part of their lives. They look at me as somebody carrying their friend around.’’

Over the years he has made himself available to hundreds of aspiring puppeteers. One, Joey Mazzarino, later became the head writer on “Sesame Street.’’ Another, John Tartaglia, went from working as Clash’s backup for Elmo to a Tony nomination as a lead character in “Avenue Q,’’ the adult-themed Muppets parody still running onstage in New York.

“When it comes to Kevin,’’ said Marks, “doors fly open.’’

She had firsthand experience as she followed him around for the documentary. “Being in his wake was like this heavenly ride,’’ she said. And Elmo loves rides.

James Sullivan can be reached at sullivanjames@verizon.net.