John "Jack" James Grundy (27 August 1926 — 1978 (aged 51–52)) born in Prescot district, was a professional rugby league footballer who played in the 1940s, 1950s, and 1960s, playing at representative level for Great Britain, and Lancashire, and at club level for United Glass Blowers ARLFC (now Eccleston Lions of the North West Men's League), New Church Tavern ARLFC, St. Helens, Barrow, and Roose ARLFC, as a second-row, i.e. number 11 or 12, during the era of contested scrums, he served in the Royal Navy aboard HMS Liverpool (C11), he died in Barrow-in-Furness, Cumbria.
Jack Grundy won caps for Great Britain while at Barrow in 1955 against New Zealand (3 matches), in 1956 against Australia (3 matches). in 1957 against France (3 matches), and in the 1957 Rugby League World Cup against France, Australia, and New Zealand (1-try).
Jack Grundy also represented Great Britain while at Barrow between 1952 and 1956 against France (1 non-Test matches).
Jack Grundy played left-second-row, i.e. number 11, in Barrow's 0-10 defeat by Wigan in the 1951 Challenge Cup Final during the 1950–51 season at Wembley Stadium, London on Saturday 5 May 1951, played left-second-row, and was voted man of the match winning the Lance Todd Trophy in the 21-12 victory over Workington Town in the 1955 Challenge Cup Final during the 1954–55 season at Wembley Stadium, London on Saturday 30 April 1955, in front of a crowd of 66,513, and played in the 7-9 defeat by Leeds in the 1957 Challenge Cup Final during the 1956–57 season at Wembley Stadium, London on Saturday 11 May 1957, in front of a crowd of 76,318.
Jack Grundy played in Barrow's 12-2 victory over Oldham in the 1954 Lancashire County Cup Final during the 1954–55 season at Station Road, Swinton on Saturday 23 October 1954.
Jack Grundy was transferred from St. Helens to Barrow for a fee of £1,000 in August 1950 (based on increases in average earnings, this would be approximately £81,710 in 2013).
Jack Grundy is tenth in Barrow's all time try scorers list with 112-tries.
Jack Grundy was the son of rugby league forward of the 1920s for Lancashire, and St.Helens Recs, Harry Grundy.