As a child he grew up in Oxford and attended Josca's Preparatory School before going to Magdalen College School. Rosenthal has always been a loyal supporter of his childhood home team of Oxford United.
His apprenticeship was served on newspapers and BBC local and national radio. In his radio career he spent time as a cricket commentator, and has even tried his hand at acting in Renford Rejects and Footballers' Wives. In his television career, which began when he joined ITV in August 1980, he has presented football, boxing and athletics, plus other minor sports. He has also been part of the teams covering World Cup Football since 1982 and The Olympics.
He was the presenter for Formula One (F1) on ITV for eight years and has presented over 150 Grands Prix since 1997. Rosenthal grew into his role as ITV F1 anchor, and gained popularity with his direct questioning of leading figures in the sport. His mastery of the well prepared, Alan Partridge-style cliché (e.g., "he's made his point with eighth place"), is something few other presenters can match.
Rosenthal was named Royal Television Society Sports Presenter of the Year in 1997 and 1999 and has won other awards at home and abroad. He was the main anchor of ITV's BAFTA winning coverage of the 2003 Rugby World Cup, which took him to Australia for the final.
2005 saw him return to boxing as ITV got back in the ring on Saturday nights. In October 2005, it was announced that Steve Rider had been recruited by ITV from BBC Sport, to assume Rosenthal's former role for the 2006 Formula One season.
Rosenthal instead became the new 'face' of ITV Champions League football coverage, as well as their boxing output. He left by saying: "Covering Formula One has been an amazing time for me and I've really enjoyed the sport, but I don't think I ever made a secret of the fact that football is my first love."
In 2006, Rosenthal worked on his seventh World Cup and he continued to front ITV's Big Fight Live boxing coverage throughout the year.
In 2006 Rosenthal made a guest appearance on Ian Wright's DVD It Shouldn't Happen To A Footballer.
In 2007 Rosenthal was the main anchor of ITV's coverage of the 2007 Rugby World Cup
It was announced in January 2008 that Jim was not going to be offered a new contract when his current ITV one expires. He continued to present ITV's boxing coverage until it came to an end after their agreement with promoter Frank Warren expired and was dropped from ITV's Champions League coverage.
Jim filmed Celebrity Superstars for Five in May 2008 at K2 Leisure Centre in Crawley West Sussex
In October 2008 it was announced Jim will return to ITV Sport to present its new boxing deal with promoter Mick Henassy and the FA Cup draw. This was seen as a major shock, as not only did ITV backtrack thier decsision to axe Jim, but also due to a condition in his contract he is allowed to work for other networks.