Wood, a consultant for private wealth and charities at lawyers Herbert Smith, has been a board member of the Charity Commission since 2008.
Wood replaces full-time chair Dame Suzi Leather, who formally stood down on Tuesday after serving two three-years terms in office.
Wood will act as chair until a full-time replacement is appointed in the autumn.
In a statement, Wood said: "I'm very pleased to have the opportunity to provide some continuity in the leadership of the commission at a challenging time when the organisation is continuing the bedding in of the major changes following our strategic review and is considering its response to Lord Hodgson's review of the 2006 act."
The Cabinet Office also confirmed that Sharmila Nebhrajani and Simon Wethered, who were due to stand down as board members in July, have been reappointed until 31 March 2013. This is intended to allow the new chair to be involved in recruiting their replacements.
The Cabinet Office added that the recruitment of a permanent chair was progressing well. A pre-appointment hearing for the preferred candidate is expected to take place in September.