Conte will be the fifth Italian to manage Chelsea, following Gianluca Vialli, Claudio Ranieri, Carlo Ancelotti and Roberto Di Matteo.
Club director Marina Granovskaia said: “We are very pleased to have recruited one of the most highly regarded managers in world football.”
Conte, who won three successive Serie A titles with Juventus, has been learning English for more than a year. As Express Sport revealed, he began talks as early as Christmas, and flew in at the weekend to clinch the deal.
Conte will bring coaches Angelo Alessio, Massimo Carrera and Paolo Bertelli, while Mauro Sandreani and brother Gianluca will also be part of his backroom staff.
Conte will have a transfer pot of over £100m to spend, partly financed by sales with up to nine players possibly leaving. Courtois, plus Radamel Falcao, Alexandre Pato, Pedro, Oscar, Nemanja Matic, Papa Djilobodji and Michael Hector could all go, with skipper John Terry’s future still uncertain.