Kermit Love, the costume designer who helped puppeteer Jim Henson create Big Bird and other “Sesame Street” characters, died June 21 of heart failure in Poughkeepsie, N.Y. He was 91.

In addition to his work with Henson, Love was a designer for some of ballet’s most prominent choreographers, including Twyla Tharp, Agnes de Mille, Jerome Robbins and George Balanchine.

Love also designed costumes and puppets for film and advertising, including the Snuggle bear from the fabric softener commercials.

“Sesame Street,” public television’s groundbreaking effort to use TV to teach preschoolers, premiered in 1969. Henson designed the original sketches of Big Bird, and Love then built the 8-foot, 2-inch yellow-feathered costume.

It was Love’s idea to add a few feathers designed to fall off, to create a more realistic feel.

“The most important thing about puppets is that they must project their imagination, and then the audience must open their eyes and imagine,” he told The New York Times in 1981.

Love also helped design costumes and puppets for Mr. Snuffleupagus, Oscar the Grouch and Cookie Monster, among other characters. He even appeared on the show himself as Willy, the fantasy neighborhood’s resident hot dog vendor.

But Love always insisted Henson’s famous frog wasn’t named for him, according to The New York Times. He said the frog was inspired by philosophy professor Kermit Smith, who died in May.

Caroll Spinney, who has played Big Bird since “Sesame Street” began, said he knew Love was gravely ill but didn’t know he’d died until Tuesday.

“Kermit was definitely a totally unique person,” 74-year-old Spinney said. “He looked very much like Santa Claus but was a little bit more like the Grinch.”

In addition to designing the Big Bird costume, he added, “Kermit really helped me with dramatic coaching, and he was wonderful at that.”

Love began making puppets for a federal Works Progress Administration theater in 1935. He also designed costumes for Orson Welles’ Mercury Theater. From there he began working with the New York City Ballet’s costumer.

In his 2003 book, “The Wisdom of Big Bird (and the Dark Genius of Oscar the Grouch): Lessons From a Life in Feathers,” Spinney recalled that after a year on “Sesame Street,” he felt he couldn’t live in New York on his salary.

Love told him to give it a month; the next week, Big Bird was on the cover of Time magazine and Spinney couldn’t imagine leaving.