Proudfoot was born in the West Country on 16 December 1972, but moved to the Midlands at a young age. He was educated at Solihull School.
His professional broadcasting career started in 1991 with the now defunct DevonAir, for whom he was a football reporter and later DJ. Proudfoot subsequently worked as a journalist and newsreader for TFM in the North-East of England before moving to Capital Gold in 1994, where he was part of the award-winning team headed by Jonathan Pearce. Later stints followed as a commentator on South Coast Radio and Xtra AM in Birmingham before a move to national radio station Talksport in 1999.
Initially employed as the station's number two commentator behind Alan Parry, Proudfoot became Talksport's lead commentator in time for the 2002 FIFA World Cup, a role that he has held for the vast majority of time since. He has subsequently commentated on both the UEFA Euro 2004 Final, and the 2006 FIFA World Cup Final for the station, and has long been established as Talksport's lead Champions League commentator.
Proudfoot also worked for satellite broadcaster Sky Sports for a number of years, specialising in commentating on Masters Football (six-a-side football for veteran and ex-players) and youth internationals. However Proudfoot was also one of the commentators on Sky's Premiership highlights programme 'Goals on Sunday' and, from 2004, 'Football First'. In 2006, he followed Sky Sports colleague Ian Crocker to Setanta Sports, where he initially commentated on Italian football but, increasingly, on the Scottish Premier League. Despite being based in Scotland, Proudfoot was also seen on a number of English Premier League games, as well as regularly commentating on FA Cup and England under-21 games. His total of more than 300 matches for the station makes him the most prolific commentator in Setanta's short history.
Following the administration of Setanta Sports's UK division in June 2009, Proudfoot's contract at the company was terminated. In July 2009, he joined ESPN as a commentator, mainly focusing on European football including Bundesliga and Serie A, but also domestic competitions from time to time.
Jim was Talksport's principal commentator at the 2010 World Cup, but announced his departure after eleven years with the station to become commentator on Absolute Radio's coverage of the Premier League. Jim has commentated on every edition of Absolute Radio's Rock 'N Roll Football, which has been nominated for three Sony Radio Academy Awards in the two years since its inception, and which won the Silver Award in the Best Sports Programme category in 2012, but in January 2014 he announced that he would be returning to Talksport in advance of the 2014 World Cup Finals. On his return to talksport Proudfoot has commentated mainly on cup competitions such as the FA Cup, League Cup, Champions League and England Internationals, he only covers Premier League games whenever Sam Matterface is unavailable as he has returned to work for the World Feed commentary of the Premier League
Jim was also part of the panel which chose the winners of the Premier League 20 Years Awards.
He is a keen follower of Torquay United F.C..
Since 2013 he has commentated on the BDO World Darts Championship from the Lakeside Country Club in Frimley Green. He is the lead commentator for the BBC (and BT Sport who share the rights) replacing David Croft who moved to Sky Sports F1. He commentated alongside Vassos Alexander and Tony Green in 2013, Vassos Alexander, Tony Green and Scott Mitchell in 2014 and Vassos Alexander, Tony Green, George Riley and John Rawling in 2015. He also worked alongside talksport colleagues Colin Murray who presents the BDO Darts for the BBC and Ray Stubbs who presents BDO Darts for BT Sport.