Roger Baker, who served in the role for four years from July 2005, is one of three people announced to have been appointed to the role by the trust’s Council of Governors.
Diane Leacock and Julie Parker will take on the other two roles.
All three new non-executive directors are due to serve a three-year term of office.
Mr Baker, who lives in Sudbury, has been working for Her Majesty’s Inspectorate of Constabulary since September 2009.
He takes over from Helen Parr whose term of office as a non-executive director (NED) expires in the autumn.
Ms Leacock and Miss Parker joined the Trust’s board of directors today to replace Professor Christine Temple, who retired on January 31, and Sir John Ashworth, who retired on Monday.
Ms Leacock, who lives in Colchester, was a NED at NHS North East Essex from July 2009 to November 2011. She has experience in senior finance roles within commercial organisations, including publishing and financial services.
Miss Parker, who has lived all her life in the area served by the trust, is a qualified accountant and has a decade of experience working as a director of resources/ and finance for three London boroughs.
Non-executive directors help develop strategy and scrutinise the trust’s performance.
NEDS at Colchester Hospital Trust are paid £11,000 a year and their duties involve a minimum commitment of four days a month.