His new deal extends his deal at Upton Park by a year to take him four years beyond the end of this season.
MD Paul Aldridge says: "He is an integral part of the club's future plans: he was as delighted to sign as we are to have him sign.
"All of our England midfield stars have committed their futures to West Ham and we are all working towards the same aim: making West Ham a successful club for years to come."
Michael said himself this week that the trials and tribulations of recent disappointing results had strengthened his resolve - echoing the thoughts of good friend Joe Cole who has repeatedly stated he would prefer to win things at Upton Park rather than anywhere else.
With Frank Lampard knocking back speculation about other clubs being after him recently, it looks as if the future of the Hammers' midfield trio is assured for years to come.
Says Harry: "Michael's new contract is great news for the club; now we have got Frank, Joe, and Michael all on long term deals.
"They really are the future for this club we have got to keep hold of the three of them."
* Fred Jarvis' highly acclaimed photographic exhibition about life behind the scenes at West Ham has now moved to the Stratford new library, where it will stay until May 27.
Entrance is, implausibly, free - and is probably the only time you will see photos of an Upton Park board meeting.
Opening times:
Mondays and Thursdays: 0800 - 2000
Tuesdays, Wednesdays, Fridays, Saturdays: 0930 - 1730
Sundays: 1300 - 1730
Fred is a lifelong West Ham supporter.