The focus of the job will be to provide advice on all football and performance matters throughout the club as well as embed and facilitate strong links between the men's and academy teams, ensuring that the various support departments are working together effectively.
Cech, who had two years with Arsenal, will be based at Cobham and will work closely with Chelsea director Marina Granovskaia. His role will also align him with the men's first team coaching and backroom staff, travelling with the team home and away with an emphasis on strategy and performance.
Cech said: "I feel very privileged to have this opportunity to join Chelsea FC again and help create the best possible high level performance environment to continue the success the club has had over the past 15 years . I'm looking forward to the new challenge and hope I can use all of my football knowledge and experience to help the team achieve even more success in the future."
Granovskaia also said: "We are delighted to welcome Petr back home to Chelsea. During his playing career here he was one of the most dedicated, successful and thoughtful professionals we have ever had. We always hoped that when Petr was ready to retire we would see him back at Chelsea FC and we are thrilled to add his expertise and knowledge of the game to the technical staff."