Beginning as a waiter, Blanc became a chef at The Rose Revived in Oxfordshire before opening his first restaurant called Les Quat'Saisons in Summertown, Oxford. He is entirely self-taught.

In 1981, Blanc opened a chain of boulangeries and pâtisseries called Maison Blanc that also contain cafès. There are currently 15 branches of Maison Blanc across the country, including several in London and one in Oxford. Maison Blanc cakes are now available nationwide in Waitrose.

Blanc opened the first of a chain of smaller restaurants, Le Petit Blanc restaurants in Oxford in June 1996. Blanc's stated aim with these was to bring the French philosophy of "good food being central to good living" to the United Kingdom. His desire was to create and serve food that can be enjoyed by everyone - "from the time conscious business person to those looking for a welcoming family restaurant". Raymond was a featured chef on Great Chefs television, appearing in Great Chefs of the World.

In June 2003, the four Le Petit Blanc Brasseries (now known as Brasserie Blanc) [1] in Birmingham, Cheltenham, Manchester and Oxford became part of the Loch Fyne Restaurant Group [2] portfolio. Since then a fifth restaurant has opened in Tunbridge Wells, Kent, another in Winchester, and one in Milton Keynes. Blanc maintains a share in the business and continues to be actively involved creating new menus, developing the chef and kitchen teams and participating in the promotion of the restaurants.

The Tunbridge Wells Brasserie recently closed and Mr Blanc has opened a new Brasserie in the prestigious lipstick tower in Gunwharf Quays, Portsmouth.

On 13 January 2007, he appeared on Saturday Kitchen. In the Omelette Challenge, he came out last because he took the longest to cook an omelette. However, he was nudged up a few places by James Martin, right above Ken Hom, as Blanc produced a black truffle out of his pocket and garnished the finished omelette with truffle shavings.

Summer 2007 saw the BBC promotion for his new reality TV programme The Restaurant airing on UK television. (The show is known to BBC America viewers in the US as Last Restaurant Standing). The promo showed a group of well-dressed diners in a slow-motion food fight, to a Gonzales backing track. The show was aired as part of BBC Two's autumn season in 2007 and returned, with minor changes to the format, in 2008. In 2009, The Restaurant returned to BBC Two in a low-budget format. This season has been much criticised for the poor standard of contestants, for neglecting the successful elements of previous series, and for Blanc choosing as the winner a team without any discernible culinary ability outside of making cocktails.

Blanc is the author of several books, including Cooking for Friends and Foolproof French Cookery. He is also one of the patrons on the Children's Food Festival, which was held on the Northmoor Trust Estate in south Oxfordshire in June 2009.

His son, Olivier Blanc, works as an assistant director on Talkback Thames's The Bill.

In the 2009 series of The Restaurant viewers made allegations that the BBC had breached its guidelines governing competitions after uproar concerning Raymond's choice of winner. The BBC repudiated this arguing that the competition required contestants who had potential for development, not just ability.