A member of a local football-playing clan Jack Eacock both grew up and went to school in Hanover Terrace, Brighton, and turned out for the town’s schools representative side before signing for the Albion as a nineteen-year-old amateur in May 1908.
His arrival at the Goldstone came shortly after he appeared for Brighton Helmston in the Sussex Senior Cup final; the West Sussex Senior League side losing 3-1 to Worthing. He had also represented Sussex vs Essex at Hastings, a performance which earned him a trial with professional side Hastings & St Leonards United.
When not required by Albion, Jack turned out for Shoreham, but he was subsequently offered professional terms at the Goldstone and was a regular in the reserves for two seasons. He made just one senior appearance, as deputy for the injured Jimmy Coleman in a 1-1 draw at Northampton during the 1909-10 Southern League championship campaign. Released in May 1910, Jack returned to local football but was briefly recalled to assist the reserves during the 1913-14 season.