That September, he and another business partner Rebecca Mascarenhas opened Elystan Street, a former site of one of Tom Aikens's eponymous restaurants in Chelsea.

He appeared in Saturday Kitchen as a guest and Great British Menu as one of its contestants, then one of its veteran chef judges.

[6][7] One night, Howard had dinner at Harveys and was impressed by the food made by its chef Marco Pierre White.

[10][11] Shortly afterwards, he worked at Bibendum as chef de partie under Simon Hopkinson, from where Howard was inspired by the emphasis on the quality and flavour of the cooking and its simplicity.

[5][13] With Howard appointed as head chef and his emphasis on simple yet elegant and contemporary French cuisine, The Square earned its first Michelin star in December 1994.

[23][24] In late January 2020, after years of MARC's financial issues and mismanagement, property administrators abruptly closed The Square during lunch service.

[31] The Ledbury had been indefinitely closed since June 2020, citing social distancing measures amid the ongoing COVID-19 pandemic as impractical for the restaurant.

[33] He has co-owned Kensington restaurant Kitchen W8 since 28 October 2009, opening it with his other business partner Rebecca Mascarenhas, who owned the site under previous names Abingdon Road and then Bistro Eleven.

[41][33] Under Howard as its current chef patron, Elystan Street earned its first Michelin star in 2017, which has been retained every year since.

[45][46] Howard also owned and operated another restaurant Union, located at the ski resort Montalbert of La Plagne (France).

He also owns a chalet there for family vacations and ski trips, having purchased it for €500,000 in 2006 and spending an additional €900,000 for home transformation.

He opened a pasta restaurant also called Notto at the Piccadilly road in November 2022 with co-partner Julian Dyer.

[62] In the seventh series of Great British Menu, alongside three other winning chefs (Colin McGurran, Daniel Clifford, and Simon Rogan), he served his winning dish (Cornish mackerel with oysters, mussels, winkles and samphire) as the fish course of the 2012 Olympians' banquet at the Old Royal Naval College in Greenwich, weeks before the 2012 Summer Olympics.

[78] On 20 July 2018 at Canterbury Cathedral, the University of Kent gave its alumni, Howard an honorary Doctor of Arts degree for his "inspirational life and outstanding contribution to hospitality and food".

[79] Howard was admitted twice to drug rehabilitation in 1995 after a three-year addiction to primarily crack cocaine, which he used to compensate his excessive workload at The Square.