The move comes after Chiefs officials denied the Rams' request to interview Vitt. The issue became moot, though, when Vitt's contract with the Chiefs expired Tuesday. Essentially a coaching free agent, Vitt then met with Rams officials and signed a contract.
"For me, it's like coming home," Vitt said. "I've been friends with [Rams presidents] Jay Zygmunt and John Shaw for years. This is the place I wanted to be."
Rams officials have declined to speculate on why the Chiefs blocked their attempt to talk to Vitt, knowing that they would eventually sign him once his contract ran out.
To replace Vitt, the Chiefs on Wednesday hired Fred Pagac, who had been linebackers coach in Oakland the last three years.
Vitt, 49, formerly worked for the Rams between 1992 and 1994 when the franchise was located in Los Angeles. He replaces Bob Babich, who left the Rams earlier this month to join the staff of former St. Louis defensive coordinator Lovie Smith, who's now coach of the Chicago Bears.
Vitt had been the linebackers coach in Kansas City the past four seasons.
A 25-year NFL veteran, Vitt is considered an excellent teacher and also had been a defensive coordinator in the league. He worked with Martz in his first stint with the Rams, when he was assistant head coach and Martz was an offensive assistant and tutored the quarterbacks.
Vitt inherits a young and athletic linebacker corps with three youngsters who can all run -- Pisa Tinoisamoa, Robert Thomas and Tommy Polley -- and were all high-round choices in the last three drafts.
Len Pasquarelli is a senior NFL writer for ESPN.com.