The co-creator of Sesame Street, the beloved US children’s educational TV series, has died aged 93.

Lloyd Morrisett’s death was announced by Sesame Workshop, the non-profit he helped establish under the name the Children’s Television Workshop.

No cause of death was given.

Morrisett and Joan Ganz Cooney worked with Harvard University developmental psychologist Gerald Lesser to build the show’s unique approach to teaching that today reaches 120 million children.

Legendary puppeteer Jim Henson supplied the creatures.

The show uses fuzzy monsters such as Elmo and the Cookie Monster to charm and teach generations around the world.

Sesame Workshop hailed Morrisett as a “wise, thoughtful, and above all kind leader” who was “constantly thinking about new ways” to educate.

Sesame Street is shown in more than 150 countries, has won 193 Emmys, 10 Grammys and in 2019 received the Kennedy Centre Honour for lifetime artistic achievement – a first for a TV program.

Tweet from @SesameWorkshop

Morrisett’s death comes less than two months after the death of another Sesame Street stalwart, Bob McGrath. The actor, musician and children’s author was a founding cast member of the show, playing friendly neighbour Bob Johnson from 1969 until 2017.

He died, aged 90, early in December.

Born in 1929 in Oklahoma City, Morrisett initially trained to be a teacher with a background in psychology.

He became an experimental educator, looking for new ways to educate children from less advantaged backgrounds.

Morrisett received his bachelor’s at Oberlin College, did graduate work in psychology at UCLA, and earned his doctorate in experimental psychology at Yale University.

The germ of Sesame Street was sown over a dinner party in 1966, where he met Cooney.

“I said, ‘Joan, do you think television could be used to teach young children?’ Her answer was, ‘I don’t know, but I’d like to talk about it,'” he recalled to The Guardian in 2004.

The first episode of Sesame Street – sponsored by the letters W, S and E and the numbers two and three – aired in 1969.

Sesame Street was designed by education professionals and child psychologists with one goal: To help low-income and minority students aged two to five to overcome some of the deficiencies they had when entering school.

Social scientists had long noted kids who were white and from higher-income families were often better prepared.

The show was set on an urban street with a multicultural cast. Diversity and inclusion were baked into the show. Monsters, humans and animals lived together peacefully.

The company said Morrisett left “an outsized and indelible legacy among generations of children the world over, with Sesame Street only the most visible tribute to a lifetime of good work and lasting impact”.

– with AAP