He began his career with Liverpool in October 1986 but never made a first-team appearance before he was sold on to Port Vale in February 1989 for a £30,000 fee.
[4] He turned professional at Kenny Dalglish's Liverpool upon completion of his Youth Training Scheme in October 1986 but was never able to provide too much first-team competition for John Barnes, and never featured at Anfield.
[1][5] Preston North End and West Bromwich Albion were also keen to sign him, but Jeffers was won over by Vale chairman Bill Bell's offer of a new Austin Montego.
[1] He was sent home from pre-season training at the University of Stirling in the summer of 1988 after Rudge caught him leading a small group of players back from a late-night drinking session.
[1] However, Jeffers again incurred the wrath of Rudge after he slapped both Tranmere Rovers's right-back and Vale's own physiotherapist during a reserve team game.
[6] He lost his first-team place in the 1994–95 season, as Vale posted a 17th-place finish in the second tier (known as the First Division due to the creation of the Premier League).
[6] Jeffers went on a one-month loan to Fred Davies's Shrewsbury Town in January 1995 and featured in three Second Division games at Gay Meadow.
[9][2] His talent made him a cult hero at Port Vale, where he was known as 'Jinking Johnny', though he could be prone to overplaying rather than delivering timely crosses.
"After retiring as a player, Jeffers wrote a column for the Liverpool Echo and worked in car financing, setting up his own company in Wallasey.