Jon Newsome was Norwich City's first £1million signing when he transferred from Leeds in July 1994. When he transferred to Sheffield Wednesday in February 1996 his career came to a full circle having commenced when he made his league debut and six consequent appearances for Sheffield Wednesday. His second club was Leeds in July 1991 and would culminate in a League Champions medal. His second spell with Sheffield Wednesday has already brought him many more appearances than his initial seven as he became a regular at centre back each week. Suffered a serious injury in the FA Cup quarter finals against Wimbledon and was ruled out for the remainder of the 1996-97 season.

On 18th November 1998, The Sun reported that Jon had joined Bolton Wanderers on a month's loan. Bradford City have since made a £1.25million bid for Newsome but were quoted £2million by the Wednesday board. Rather high for a player who had not made any appearances for Wednesday in 18months due to injury and was nearly forced to quit this last summer. The Daily Mirror claimed on Monday 8th February 1998 that Ron Atkinson was to sign Jon for his beleaguered Nottingham Forest defence. Supposedly this £1.5million deal was arranged before Forest conceded 8 at home to a rampant Manchester United. Birmingham City made a bid of £1.5million for Jon in mid February 1999 as a replacement for the injured Gary Ablett. The Blues wanted to pay this fee over three years but Wednesday refused, seeking the money in two. Hence Wednesday refused. Bradford's promotion to the Premiership has led Teamtalk to again link Newsome with a move to Valley Parade although they claim fellow promotion seekers Birmingham, Bolton and Watford would also be interested in his services.

Along with nine other first teamers, Jon was placed on the transfer list at the end of May 1999 with Wednesday seeking £1.5million for his services as they attempt to rebuild their side. Jon didn't move on during 1999 or the early part of 2000 but his future remains unsettled as his contract expired in the summer of 2000 On 19th May 2000, Jon announced his retirement from the game, at the early age of 29, due to his knee injury. Maybe it was the prospect of playing in Division One with Wednesday after their relegation that prompted his action ?

Jon then worked for Wednesday's academy as a coach, and then spent time at Grimsby as a coach with their Centre of Excellence and as a scout. On 11th April 2002, Dr Martens' League side Gresley Rovers announced Jon's appointment as manager to replace John McGinley. Gresley finished 6th that first season under Jon's stewardship. He then spent the 2002 summer boosting his squad for the new campaign signing a new Assistant Manager (Alan Tittleton) and adding Craig Hopkins, Gary Smith, Jamie Barratt, Michael Crawford (Tamworth), Gary White and Gary Moran (Grimsby) to his ranks. He has also registered himself as a player, in case of emergencies.

At the end of June 2003, Newsome rocked Gresley when he announced his resignation for family reasons. "It was a difficult decision but my family have to come first...the decision had nothing to do with another club but at some stage I would like to get back into full time football..my decision was for purely personal reasons..I have had a fabulous time working with Gresley and thoroughly enjoyed last season. Gresley gave me my first chance in management and I'm thankful for that.. I have learned an awful lot." (Non-League Paper, 29 June 2003). This experience combined with a UEFA A coaching badge should stand Jon in good stead for when he returns to management.

In August 2004, Jon was found helping out at Spalding United and it was hoped that he would turn out for Spalding in defence.

It was reported in January 2012, in conjunction with the Jonny Howson transfer, that Newsome runs a prestige car company in Sheffield.