Cumberland, the scrum coach with the Highlanders until 2008 under former coaches Glenn Moore and Greg Cooper, is returning from Japan to take up his old role, while Keane will be the third coach, alongside head coach Jamie Joseph and assistant coach Simon Culhane.
Joseph said it was good to get his coaching team finalised so when the team was selected they could hit the ground running.
Cumberland was experienced in the scrummaging role, and Joseph said it was vital to have someone fully involved in what was a vital part of the game.
Cumberland, who played 81 games for Otago from 1988 to 1993 was working out his notice with his Japanese side, Kobe Steel, and would join the Highlanders early in the new year.
The Highlanders scrum was coached last year by New Zealand Rugby Union scrum coach Mike Cron, with former Otago prop Keith Cameron involved.
Joseph said Keane would bring a lot of experience to the side.
He is coaching Tasman this season and had previously coached Hawkes Bay and club and school teams.
"He has coached at all levels and that depth of experience he brings will be really vital to us. Next year with the wider training group there are going to be 40 players involved and you need quality people for those players. It is not just about the first XV," Joseph said.
Joseph said coaches would not be pigeon-holed into roles and would be free to contribute in all areas.
"The fact is in modern rugby many people want to define roles but it is not like that at all. At the moment Kieran is coaching the forwards while last year the All Black coaches all changed around."
Keane would spend six months in Dunedin and said he was very much looking forward to the new role.
"I know Jamie is very keen to have a new broom through the place and he is obviously looking to do things a little differently. Creating our own culture is exciting in itself."
Keane had spent five years at the University of Otago in the 1970s, although he never played for Otago.
"I'm really happy to be working alongside people who I respect and have a lot of time for."
He has signed a six-month contract with the Highlanders and will then return north to coach Tasman in the ITM Cup next year.
He played six games for the All Blacks in 1979 at second five-eighth but did not play a test.
The new coaching trio replace Glenn Moore, Peter Russell and Barry Matthews.
The Highlanders will be named on November 10.
