With the announcement of the host countries for the two tournaments due to be announed in December, Dein will play a key role in the bid along with board chairman Lord Triesman.
And an FA statement said: "Dein will share with the chairman, David Triesman, a key role in the international promotion of England's campaign to host the FIFA World Cup. His appointment begins immediately."
"David has a huge amount of experience in world football and an excellent network of contacts. We are very pleased that he will be joining the team in such an important role for the crucial final 10 months," Triesman said according to Press Association.
"We are happy with the way the bid is progressing but it is important to keep the momentum building in any campaign, and to peak at the optimum moment, and we are sure David can achieve that with us."
Dein has previously also been vice-chairman of the FA and chairman of the now-defunct G14 group of 'elite' clubs.
He was delighted to have been handed the challenge of such a prestigious role.
"I am delighted to be part of the 2018/22 bid and look forward to an exciting campaign," he said.
"Having had 25 years in English, European and world football this was a challenge I could not refuse. Now the hard work begins."