"This has been a remarkable period in the history of cricket in England and Wales and I have been extremely proud to having been able to play a part in it," Morris said in a statement on the ECB's website (www.ecb.co.uk).
"It has been my privilege to work with Andy Flower, the England team director, during the last four years and congratulate the players on their three Ashes series successes, being the number one ranked team in the world in all three formats of the game, and also winning one ICC global event (2010 Twenty20 World Cup) and being runners-up in another.
"I am sure they will go on to even greater achievements in the future."
The ECB will now start the search for his successor.
(Reporting by Josh Reich; Editing by John O'Brien)
