Peter Kenyon will start his new role at Stamford Bridge as Chelsea chief executive on 1 February.
Kenyon stepped down as Manchester United chief executive in September but had been on "gardening leave" while the two clubs wrangled over his release.
A statement issued on Kenyon's behalf said: "Kenyon will join Chelsea Village plc as chief executive on 1 February."
"Manchester United and Chelsea have reached a mutually satisfactory settlement regarding his resignation."
The statement added: "Peter is pleased that the negotiations have been amicably concluded and
greatly looks forward to the challenges that await him at Chelsea."
Manchester United decided to keep Kenyon under contract until the summer - unless Chelsea came up with a compensation package.
Old Trafford chiefs were partly worried that Kenyon could use his inside knowledge of the club to influence some of Chelsea's transfer activity.
But this problem was solved by ensuring that Kenyon could not take up the Chelsea post until after the transfer window has closed.