Rambis, 56, won eight combined NBA titles as a player and an assistant coach with the Los Angeles Lakers, where he finished his third stint on the coaching staff last season.
Fisher, set to coach his first season in the NBA in 2014-15, spent 10 seasons with Rambis during his playing career.
Knicks president Phil Jackson said he, Fisher and Rambis shared a similar approach to the game.
"Together, Derek and I have started assembling a coaching staff to lead this team on and off the court," Jackson said on Monday.
"The three of us are similar in our philosophies and our approach to the game."
Fisher, who finished his career at the Oklahoma City Thunder at the end of the 2013-14 season, said Rambis' experience made him a key hiring.
"Kurt is exactly the type of person we want in our organisation to help develop our culture of success," he said.
"His vast knowledge and experience as a championship player and coach are traits that we embrace adding to our staff."