The appointment had been expected after Microsoft Corp. entered into a cooperation agreement with ValueAct in August following its purchase of some 66.9 million shares, or about 0.8 percent of the outstanding shares. That stock is currently worth about $2.55 billion,
ValueAct has said investors should value Microsoft for its enterprise software products and cloud computing business rather than its flagship Windows computer operating system.
Microsoft's board now has 11 members, including former CEO Steve Ballmer, founder Bill Gates, new CEO Satya Nadella, and others.
Board chairman John Thompson said Morfit brings valuable insights to the board given his financial background, extensive experience as a public company director and perspective as a significant shareholder.