England head coach Stuart Lancaster highlighted Catt, capped 75 times by England and a World Cup winner in 2005, as a key ingredient to his backroom staff.
He took the job on an interim basis during the summer tour of South Africa and, after compensation was agreed with club side London Irish, he is now ready to get started.
“I loved working with the squad in South Africa and, while gutted not to win the series, I can see that this group of players is heading in the right direction,” he said.
“Stuart, Graham [Rowntree] and Andy [Farrell] did a fantastic job in the Six Nations and to be able to work with them and the best players in England is a great honour.”
Utilised as a fly-half, full-back and inside centre during his 13-year international career, Catt brings a wealth of experience to the role.
And Lancaster tipped him to make a big impact before the eagerly-awaited autumn internationals against Australia, South Africa and New Zealand.
“I’d like to thank London Irish for reaching a compromise with us and allowing Mike to start immediately,” said Lancaster.
“Mike made a big impression in South Africa, both on the players and the management.
“We have a massive challenge ahead of us with the internationals in November, but beyond that we need to ensure we have the highest standards across all our representative teams and programmes and Mike will help deliver those.”
© Sportsbeat 2012
MORE: The latest football news
MORE: The latest tennis news
BIOGRAPHY: Ethan Hazard
BIOGRAPHY: Daniel Sturridge