The new deal, announced by the team on Sunday, will see the number one pick from the 2005 draft remain in Kansas until the end of the 2018 season
Chiefs head coach Andy Reid could not be happier to have Smith on board for an extended period of time, saying the 30-year-old is a key figure in his side.
"John [Dorsey, chiefs general manager] and his staff have worked hard to get this deal done. They’ve done a nice job," Reid said.
"Alex is a smart, talented football player that has adapted well to our offensive scheme. He also, obviously, has had a tremendous amount of success as a quarterback in this league.
"We as a team are very happy to have Alex as our quarterback moving forward."