The Kansas City Chiefs must have liked what time head coach.
Crennel was given the job on an interim basis when Todd Haley was fired on December 12.
The Chiefs proceeded to win two of their final three games under Crennel, handing Green Bay its lone loss of the season and beating Denver to close out a 7-9 campaign. The lone loss came in between against Oakland in overtime.
"We are very excited to name Romeo the new head coach of the Chiefs," said team CEO Clark Hunt in a statement. "In 30 years as a coach in the National Football League, Romeo has established an outstanding track record of success, and we believe his experience and proven ability make him the best person to help us reach our goal of consistently competing for championships."
Crennel was the head coach of the Cleveland Browns from 2005-08 and compiled a record of 24-40, then joined Haley's staff as defensive coordinator for the 2010 campaign. The Chiefs went on to win the AFC West last season.
"I believe in the types of players that we are trying to win with and the identity we are trying to create," Crennel said Monday. "It is a rare opportunity to be a part of an organization like the Kansas City Chiefs with its storied history and passionate fans and I am eager to get to work and bring this franchise and our fans the success they deserve."
Before his first NFL head coaching experience in Cleveland, Crennel was a long time assistant. He was part of two Super Bowl championships during a 12-year run from 1981-92 with the New York Giants and added another Super Bowl berth during a stint in New England from 1993-96.
After a three-year tenure as defensive line coach with the New York Jets from 1997-99 and a year in Cleveland as defensive coordinator, he went back to New England and was in charge of a defense from 2001-04 that helped the Patriots to three Super Bowl titles.
"Romeo's vast experience and intelligence have helped him achieve success at the highest level," said Chiefs general manager Scott Pioli. "The way in which he creates accountability and respect amongst the team creates a very productive work environment and will be critical in continuing to develop our young core of players. In addition, Romeo's extensive knowledge of our players, personnel, and needs make him a perfect fit to lead the Kansas City Chiefs."
Crennel was also an assistant at the collegiate level from 1970-80.