Kenneh has been with the Whites for almost eight years and the 19-year-old has regularly featured on the first team bench during the 2021-22 Premier League campaign.
The teen was never handed a first-team debut but was booked for his celebrations as a substitute following Luke Ayling's dramatic late winner in March's 3-2 win against Wolves at Molineux.
Kenneh was again on the bench for United's final home game of the season against Brighton last weekend but the youngster announced on Monday evening that he was leaving the Whites as Hibernian confirmed his capture.
Kenneh's existing Whites deal expired at the end of June and the teen will join Hibs on July 1.
United wanted to keep the versatile centre-back or defensive centre midfielder and offered the youngster a new deal.
Writing on his Instagram page, Kenneh said: "Still can't believe I'm writing this but after nearly eight years at Leeds United my time here has come to an end.
"I have had so many great memories and experiences along the way, from winning player of the tournament in the Galway Cup to winning the PL2 league last season, and of course getting my first yellow card in the Prem.
"I would like to thank all the players and coaches that I have played and worked with over these years; together you made me a better player and person and I will never forget how fortunate I was working with you daily.
"And to the fans, what can I say.
"I wish I could've had more memories with you together.
"Thank you for your incredible support and sure we will cross paths again in the future."
News of Kenneh's capture was announced on Hibernian's official website.
The club are now managed by Lee Johnson who said: “We’re delighted to welcome Nohan to Hibernian FC.
"He adds something extra to our squad and although his primary position is defensive midfield, he also offers us the versatility to play at the back.
“He’s a young player with a big presence and a lot of quality. He has a real desire to develop and play First Team football regularly.
“Nohan has had interest from around the UK and abroad, so this signing is a real coup for us.
"To reach his potential, he has to have the right attitude and desire to be the best he can.
“We are looking forward to working with him and welcoming him to the Hibs family.”
The club's head of recruitment, Ian Gordon, added: “Nohan is a really exciting young player that has a lot of potential and a number of quality attributes that will fit our style of play.
“This fits the model we are trying to introduce here at Hibernian FC, bringing in young, talented players that will not only strengthen our First Team, but ones that we can develop into even better players. This is a really positive signing for the Club.”