Nicolas Hieronimus joined L'Oréal in 1987 as Product Manager. As marketing Director for the Laboratoires Garnier in 1993, he successfully created the Fructis haircare range. In 1998, he became General Manager of the Garnier Maybelline Division in the UK. In 2000, he was named General Manager, L'Oréal Paris France, and then International General Manager for L'Oréal Paris, which he repositioned as the "accessible luxury" brand. In 2005, he became General Manager of L'Oréal Mexico. In 2008, he became General Manager of the L’Oréal Professional Products Division and he increased its global leadership. In January 2011, he was appointed President L’Oréal Luxe, a role that he held until the end of 2018. In addition, he took up a new position as President Selective Divisions (Luxury, Active Cosmetics, Professional Products,) on 1 July 2013 and he was named Deputy CEO in charge of Divisions on May 1, 2017. In May 2021, he was appointed as CEO, as well as member of the Board of Directors.