The Rams (8-8) needed a win and help to get into the playoffs and made it when Minnesota (8-8) lost, 21-18, to Washington.
The Jets (10-6) backed into the playoffs when Buffalo lost to Pittsburgh, 29-24.
Marc Bulger connected on 29 of 39 passes for 450 yards and three touchdowns for St. Louis, which would win the NFC West if Seattle lost later to Atlanta.
Torry Holt caught seven passes for 116 yards and two touchdowms and became the first player in NFL history to have at least 1,300 receiving yards in five straight season.
Curtis Martin ran for 153 yards for the Jets and is fourth on the NFL's all-time rushing list with 13,366 yards.