Thomas Kelsey (died c. 1680) rose from obscurity as a "London tradesman" to become an important figure in the government of Oliver Cromwell.
Kelsey enlisted in the New Model Army and fought on the side of Parliament during the English Civil War, displaying a zeal that led him to become a major-general in 1645.
As a member of the 'fifth Monarchist congregation' in London, led by John Simpson, during the early 1650s, he supported Oliver Cromwell in the establishment of the Protectorate and was elected MP for Sandwich in Kent for the First Protectorate Parliament, and was appointed the Major-General for Surrey and Kent during the Rule of the Major-Generals.
Thomas Kelsey was returned for Dover during the Second Protectorate Parliament, when he supported John Desborough's move to establish the Major-Generals as a permanent form of government.
Major-General Kelsey was deprived of his commands under the recalled Rump Parliament (Jan 1660), and was ordered to leave London.