A goal-kicking stand-off, he gained a high level of prominence in the sport in England by playing for Hull Kingston Rovers (captain) and Castleford, as well as representing Great Britain.
He made his début on 3 October 1964 against Dewsbury Celtic, and won his first domestic honours in 1965 with Castleford picking up the Floodlit Trophy.
Millward played in the position of Stand-off and, due to the importance of such a position in rugby league, and due to the fact there were many more experienced players in the Castleford side at that time (such as Alan Hardisty and Keith Hepworth) Millward found it hard to break into the first team for any length of time.
In the mid-1970s Hull Kingston Rovers had become a dominant force in the world of rugby league thanks in part to Millward's playmaking abilities.
Millward made 14 appearances during his time in Sydney, and scored one try as well as kicking 17 points for the then struggling club before returning to Hull.
In 1977 Millward was named as player-coach of Hull Kingston Rovers after the unfortunate death of the club's former manager Harry Poole.
in the Challenge Cup Final, despite breaking his jaw midway through the first half, Millward continued and was awarded the trophy at the end of the game.
in the 1967–68 Yorkshire Cup Final during the 1967–68 season at Headingley, Leeds on Saturday 14 October 1967, played Stand-off, and scored 4-conversions in the 11–7 victory over Castleford in the 1971–72 Yorkshire Cup Final during the 1971–72 season at Belle Vue, Wakefield on Saturday 21 August 1971, played Stand-off, and was man of the match winning the White Rose Trophy in Hull Kingston Rovers' 16–13 victory over Wakefield Trinity in the 1974–75 Yorkshire Cup Final during the 1974–75 season at Headingley, Leeds on Saturday 26 October 1974, and played Stand-off, and scored a drop goal in the 11–15 defeat by Leeds in the 1975–76 Yorkshire Cup Final during the 1975–76 season at Headingley, Leeds on Saturday 15 November 1975.
Millward’s international career was important as he was an integral member of Great Britain’s last Ashes winning Tour to Australia in 1970 and the last time any series was won against the Australians.
Again, Millward rose to the occasion: with approximately five-minutes to go he scored the match and series winning try on the Sydney Cricket Ground (SCG).
Thereafter, Millward played with distinction for Great Britain in various internationals against the other nations, but a winning series against the Australians proved elusive.
[14] During the 1978 Kangaroo tour Millward captained Great Britain from stand-off in all three Test matches of the Ashes series which Australia won 2–1.
Millward coached Hull Kingston Rovers to the John Player Trophy Final which they lost and second in the Division One Championship.
Roger Millward was the coach in Hull Kingston Rovers' 9–18 defeat by Widnes in the 1980–81 Challenge Cup Final during the 1980–81 season at Wembley Stadium, London on Saturday 2 May 1981, in front of a crowd of 92,496, and was the coach in the 14–15 defeat by Castleford in the 1983–84 Challenge Cup Final during the 1984–85 season at Wembley Stadium, London, on Saturday 3 May 1986, in front of a crowd of 82,134.
By 2009 Hull Kingston Rovers had revived its fortunes, riding high in 4th place in the Super League, and regularly fills the new Craven Park, and the Roger Millward Stand.
Millward was most recently employed as a Premises Manager by Royds Specialist Language College, near Rothwell Sports Centre.
[20] As a player As a coach Individual Arriva Yorkshire honoured 13 rugby league footballers on Thursday 20 August 2009, at a ceremony at Wheldon Road, the home of Castleford.