He played at club level for Dewsbury, York, Wakefield Trinity (captain), Hull FC and Warrington, as a wing, centre, or stand-off.
Terry Day played on the wing in Dewsbury's 22–13 victory over Leeds in the Championship Final during the 1972–73 season at Odsal Stadium, Bradford on Saturday 19 May 1973.
Terry Day played at centre in Hull FC's 14–14 draw with Widnes in the 1981–82 Challenge Cup Final during the 1981–82 season at Wembley Stadium, London on Saturday 1 May 1982, in front of a crowd of 92,147, but was replaced by James Leuluai in the replay.
He appeared as a substitute (replacing scrum-half Kevin Harkin) in the 12–14 defeat by Featherstone Rovers in the 1982–83 Challenge Cup Final during the 1982–83 season at Wembley Stadium, London on Saturday 7 May 1983, in front of a crowd of 84,969.
[6] Terry Day played at centre in Dewsbury's 9-36 defeat by Leeds in the 1972–73 Yorkshire Cup Final during the 1972–73 season at Odsal Stadium, Bradford on Saturday 7 October 1972, in front of a crowd of 7,806, played at centre (replaced by substitute John Crossley Jr.) in York's 8-18 defeat by Bradford Northern in the 1978–79 Yorkshire Cup Final during the 1978–79 season at Headingley, Leeds on Saturday 28 October 1978, in front of a crowd of 10,429, and played at centre in Hull FC's 18–7 victory over Bradford Northern in the 1982–83 Yorkshire Cup Final during the 1982–83 season at Elland Road, Leeds on Saturday 2 October 1982, in front of a crowd of 11,755.