Prout was a restricted free agent who could have received offers from other teams beginning on Tuesday.
The 24-year-old Prout has three goals and 10 assists in 82 career NHL games, all with Columbus. He has a rating of plus-9 with 62 penalty minutes.
Last season, the 6-foot-3, 222-pound Prout had two goals and four assists in 49 games, finishing seventh on the Jackets in blocked shots (65).
He was the club's seventh pick, 154th overall, in the 2010 draft.
The contract was announced on Saturday.