Buckner was educated at St. Petroc's preparatory school in Bude, Cornwall where he won the Victor Ludorum trophy in 1975, as well as a scholarship to Worksop College in Nottinghamshire.

Representing England, the 1986 Commonwealth Games in Edinburgh, Scotland, was his first major race and he performed brilliantly finishing with a silver medal in 13:25.87 behind fellow countryman Steve Ovett.

Shortly after his running career ended, Buckner worked for Adidas before he and his family moved to New Zealand to concentrate on apple farming.

[citation needed] This was unsuccessful and they returned to the United Kingdom; Buckner was appointed project director of the athletics board.

[clarification needed] Jack's younger brother Tom Buckner was also an international distance runner and gained recognition when he finished 5th at the 1994 Commonwealth Games 3000m steeplechase (8:29.84).