The appointments include Waitrose managing director Mark Price, former Aegis chief financial officer Alicja Lesniak, litigation lawyer Monica Burch and Richard Rivers, former chief of staff and head of corporate development at Unilever.
Each appointment is for an initial term of three years, starting on 1 October, and each director will work one day a month for £22,177. According to Channel 4's annual report for 2009 its non-executive directors were paid £23,000 a year.
Colette Bowe, chairman of Ofcom, said: "The combination of the new appointments and the extensions is intended to bring some new high-quality commercial and professional skills onto the Channel 4 board while also providing stability by retaining some very strong individuals for the forthcoming year."
In addition to his role as Waitrose managing director Price is also chair of the Prince's Rural Action Programme as part of Business in the Community and a board member of the Consumer Goods Forum.
Lesniak has also worked at the creative networks BBDO Worldwide and Ogilvy and Mather Worldwide and is currently a non-executive director of property company DTZ and recruitment company SThree.
Rivers is a non-executive director of Mothercare and Burch is chairman of the board at law firm Addleshaw Goddard and head of its consumer and IP litigation practice.
Ofcom appoints Channel 4's non-executive directors under the Broadcasting Act 1990.
In addition to the hires, Stephen Hill's term has been extended until end of December 2011 and the terms of office for Martha Lane-Fox and Lord Puttnam, the deputy chairman of Channel 4, have been extended until 31 January 2012.
Lord Burns, Channel 4 chairman, said: "The four new non-executive directors join us as we enter a moment of change and creative renewal, led by David Abraham and his newly formed management team, and I look forward to working closely with them during the exciting challenges ahead."