 Born in Shotts, North Lanarkshire, Walker played for local team Armadale before being recruited by leading club Hearts, making his league debut for the Edinburgh club on 18 February 1893.He played four full seasons with Hearts, winning two League Championships and one Scottish Cup, and was nearing the end of a fifth campaign when he was signed for Liverpool by manager Tom Watson along with teammate Tommy Robertson for £350 on 30 March 1898.He made his "Reds" debut in a Football League Division One fixture on 11 April 1898.