Marrone, 48, coached Syracuse the last four seasons, posting an 8-5 overall mark and 5-2 Big East record in 2012. That left him 25-25 in his career as head coach. While the .500 mark isn't imposing, the Orange were 10-37 in the four seasons before Marrone took over.
He previously worked in the NFL as offensive coordinator for the New Orleans Saints from 2006-08 and offensive line coach for the New York Jets from 2002-05.
Marrone replaces Chan Gailey, who was 34-46 in three seasons as the Bills coach. Buffalo was 6-10 in 2012, missing the playoffs for a 13th consecutive season.