The announcement was made on Twitter by agent Mike McCartney, who did not disclose terms of the deal.
Schwartz, 30, was a first team All-Pro last season, the first such honor of his career.
He has been with the Chiefs since 2016 when he joined the team as a free agent with a five-year, $33 million contract. He spent the first four seasons of his career with the Cleveland Browns, who selected him in the second round (37th overall) of the 2012 draft.
Schwartz has not missed a game in his NFL career, starting each of the 112 games he has played in.