The 41-year-old replaces Enzo Maresca, who left on New Year’s Day (01.01.26) after a poor run of form and a breakdown in relations with the board, with Rosenior arriving from sister club Strasbourg under BlueCo ownership.
Speaking to Chelsea’s official website, he said: “I am extremely humbled and honoured to be appointed head coach of Chelsea Football Club. This is a club with a unique spirit and a proud history of winning trophies.
“My job is to protect that identity and create a team that reflects these values in every game we play as we continue winning trophies.”
Rosenior - who signed a long-term contract running until 2032 - confirmed he had agreed terms prior to the club’s formal announcement and revealed the scale of interest he turned down to take the role.
Speaking ahead of his unveiling, he said he had “interest from many clubs, including Champions League clubs”, but he “cannot turn down Chelsea”.
He continued: “To be entrusted with this role means the world to me and I want to thank all involved for the opportunity and faith in undertaking this job.”
The former Hull City manager will be joined at Stamford Bridge by assistants Kalifa Cissé and Justin Walker, as well as head of analysis Ben Warner, as he returns to England after a successful spell in France.
He said: “I believe deeply in teamwork, unity, togetherness and working for one another, and those values will be at the heart of everything we do. They will be the foundation of our success.”
Chelsea Under-21s boss Calum McFarlane oversaw a 1-1 draw with Manchester City in the interim period, while the club were also linked with high-profile names including Xavi and Bournemouth head coach Andoni Iraola.
Outlining his vision at Chelsea, he added: “I am excited to work with this extremely talented group of players and staff, to build strong connections on and off the pitch, and to create an environment where everyone feels united and driven by the same goal.
“There is a real hunger to win, and I will give everything, every single day, to help this team compete and win at the very highest level to make everyone connected and proud to be a part of Chelsea Football Club.
“I want our fans to be proud of who we are and what we represent in every single game that we play. They are the soul of this enormous, historic and huge football club.”
