Browns played in the NFL championship game 1950-1955 and won three. 1957 they played in the league championship game. Between 1964 and 1972 they were a playoff team 7 times and won the championship in 1964. Between 1980 and 1989 they were in the playoffs seven times. They were a playoff team in 1994 under Bill Belichick.
For comparison, during the period of 1950-1971 the mighty Steelers never made a single playoff. They were shit until 1972 after the Paul Brown trained and retired Cleveland Brown guard and Cleveland native Chuck Noll took over. If only the Browns had hired Noll as head coach in 1969 instead of letting him work in Pittsburgh it is a fact that the Browns would have never lost a single game from 1969 through 1991. The spawn of Satan Art Modell destroyed his team.