The first series that featured Jamie Oliver was The Naked Chef on BBC Television. The title was a reference to the simplicity of Oliver's recipes, and has nothing to do with nudity. Oliver has frequently admitted that he wasn't entirely happy with the title, which was devised by producer Patricia Llewellyn. (The opening titles include a clip of him telling an unseen questioner "No way! It's not me, it's the food!") The success of the programme led to the books Return of the Naked Chef and Happy Days with the Naked Chef. His work on the Fifteen restaurant was shown as Jamie's Kitchen and Return to Jamie's Kitchen on Channel Four. His programmes are shown in over 40 countries, including the USA's Food Network, where he is the second most popular presenter. Oliver's Twist and Pukka Tukka picked up where The Naked Chef left off. Jamie's Great Escape (also known as Jamie's Great Italian Escape), a travelogue series, was first broadcast on Channel 4 in the UK in October 2005.

In 2005 Channel 4 screened Jamie's School Dinners (Broadcast as Jamie's School Lunch Project in the United States), in which Oliver took over responsibility for running the kitchen meals in Kidbrooke School, Greenwich, (the UK's first comprehensive) for a year. Disgusted by the unhealthy fare being served to schoolchildren and the lack of healthy alternatives on offer, Oliver began a campaign to improve the standard of Britain’s school meals. Public awareness was raised, and, subsequent to Oliver's efforts, the UK Government pledged to spend £280m on school dinners (spread over three years). Tony Blair himself acknowledged that this was a result of Oliver's campaign. Following the success of the campaign, Oliver was named "Most Inspiring Political Figure of 2005" in the Channel 4 Political Awards 2006.