Holliday made steady progress, starting out as a stand off and alternating in the centres and within four years of his début, he represented Great Britain, partnering Don Fox, in an unofficial 18–10 victory over France at Odsal Stadium, Bradford in 1956.
The try-maker turned try scorer with two scorching tries at Wembley in 1960, when Trinity defeated Hull FC, 38–5 to win the RL Challenge Cup.
[7] Keith Holliday played stand-off for Great Britain while at Wakefield Trinity in the 18–10 victory over France (non-Test match) at Odsal Stadium, Bradford in 1956.
[8] Along with Billy Banks, Ted Cahill, Gordon Haynes, Billy Ivison, Bob Kelly, John McKeown, George Parsons and Ted Slevin, Keith Holliday's only Great Britain appearance came against France prior to 1957, these matches were not considered as Test matches by the Rugby Football League, and consequently caps were not awarded.
[9] Keith Holliday played scrum-half in Wakefield Trinity's 3–27 defeat by Wigan in the Rugby Football League Championship Final during the 1959–60 season at Odsal Stadium, Bradford on Saturday 21 May 1960.
in the 1959–60 Challenge Cup Final during the 1959–60 season at Wembley Stadium, London on Saturday 14 May 1960, in front of a crowd of 79,773, played scrum-half in the 12–6 victory over Huddersfield in the 1961–62 Challenge Cup Final during the 1961–62 season at Wembley Stadium, London on Saturday 12 May 1962, in front of a crowd of 81,263, and played scrum-half in the 25–10 victory over Wigan in the 1962–63 Challenge Cup Final during the 1962–63 season at Wembley Stadium, London on Saturday 11 May 1963, in front of a crowd of 84,492.
Gained Yorkshire county honours and a Great Britain place against France at off-half, and had experience also at centre for his Club before changing to the scrum-half berth.
[13] Keith Holliday's marriage to Betty (née Simpson, death circa 18 August 2019) was registered during first ¼ 1956 in Lower Agbrigg district.