Roger joined the Castleford Tigers in 1964. Roger played 40 games for Castleford over 2 seasons (16 tries, 35 goals). In 1966 Roger joined Hull KR. Roger played in Hull KR’s 1967-68 Championship Final. In 1969, Roger was appointed captain of Hull KR. In 1977, Roger became captain-coach of Hull KR. Roger led Hull KR to the 1978-79 Championship. Roger also led Hull KR to win the 1980 Challenge Cup. Roger played 413 games for Hull KR over 14 seasons. (207 tries, 597 goals, 10 field goals). In 1976 Roger played 14 games for the Cronulla Sharks (1 try, 17 goals).
Roger played 12 games for Yorkshire from 67-75 (8 tries, 22 goals). Roger played 29 test matches for Great Britain from 1966-79 (17 tries, 15 goals). Roger played 17 test matches for England from 1966-80 (3 tries, 10 goals).
Roger coached Hull KR from 1980-91. During this time, Roger coached Hull KR to; the 1981 Challenge Cup Final, The 1984 Championship and the 1986 Challenge Cup Final. Roger coached Halifax in the 1991-92 season, and Roger coached York in 1994.
Roger passed away on May 2 2016.
In 1983, Roger was made a Member of the Most Excellent Order of the British Empire (MBE). In 2000 Roger was inducted into the British Hall of Fame. After Roger passed away, Hull KR retired the number 6 jersey. In 2018, Hull’s Garrison Road was renamed Roger Millward Way.