Whittaker was a free agent after having refused to accept the transfer of his contract to newco Rangers.
The Scotland international has agreed on a four-year contract with Norwich City.
“In Steven we have a player who is very versatile. He can play anywhere across the back four and anywhere across midfield, so there’s plenty of versatility there,” Norwich boss Chris Hughton told the club’s official website.
“It’s probably a good time for him. Sometimes it is time to move on to a different club, and go there with a lot of enthusiasm, and he has international experience too.
“He has of course been used to playing at a very high level when he was at Rangers, and in a lot of big games with a passionate crowd behind him. So the stage of the Premier League is certainly one that won’t faze him with his experience.”
Whittaker said: “All of my experience to date has been in Scotland so I’m really looking forward to the challenge of playing in the Premier League, I’m very excited about it.
“When I spoke to Chris Hughton I was very impressed with his plans to progress Norwich City and everyone I’ve spoken to in the game has had nothing but praise for the club and the city of Norwich.
“I know Simon Lappin from a few years back and of course I know Russell Martin from Scotland and I’m looking forward to meeting up with the squad and the staff.”
