Pedder was born in London, the eldest son of John Pedder, a barrister. Pedder junior was educated at Charterhouse and the Middle Temple from 1818 where he was called to the bar in 1820. Then he entered Trinity Hall, Cambridge, graduating LL.B. in 1822.
Pedder was appointed chief justice of Van Diemen's Land on 18 August 1823. Pedder sailed in the Hibernia, arriving in Hobart with his wife Maria, a daughter of Lieutenant-Colonel Everett, on 15 March 1824. On 24 May, Joseph Gellibrand, the first Tasmanian Attorney-General, in an inaugural address to the Supreme Court, spoke of trial by jury as being "one of the greatest boons conferred by the legislature upon this colony". It was questioned, however, whether this right was not taken away by section 19 of the "Act for the better administration of justice in New South Wales and Van Diemen's Land", and Pedder in a long and weighty judgment took this view. As Chief Justice, Pedder was automatically a member of the Legislative Council and the Executive Council, which necessitated a very close relationship with Governor Arthur and even led to him being referred to as belonging to the "government party". The Chief Justice should not have been put into such a position, and in 1851, when the new partly elected legislative council was formed, the Chief Justice was no longer one of the government nominee members. Fenton[who?], in referring to this, says that, although Pedder was "a very useful member of the old council", he was "now wisely removed from the disturbing arena of political strife".
On 19 July 1854 Pedder had a paralytic seizure while on the bench, and shortly afterwards retired on a pension of £1500 a year under an act passed in the previous May. Pedder's wife died on 23 October 1855 after suffering from paralysis. Pedder returned to England and died in Brighton on 24 March 1859. He was knighted in 1838. As a judge he has been called slow in decision and fearful of overstepping the written word of a statute. He was not a great lawyer, but he was upright and thorough, always careful that the accused should suffer no injustice. Fenton, who had personal knowledge of him, says that his "prudence and foresight often prevented grave injustice and dangerous blunders in the administration of affairs under the peculiar and difficult conditions of a colony half bond and half free".
Lake Pedder in south-west Tasmania was named after him.
- P. A. Howell, 'Pedder, Sir John Lewes (1793–1859)', Australian Dictionary of Biography, Vol. 2, MUP, 1967, pp 319–120. Retrieved 2009-11-03
- "Pedder, John (PDR822J)". A Cambridge Alumni Database. University of Cambridge.
- Serle, Percival (1949). "Pedder, John Lewes". Dictionary of Australian Biography. Sydney: Angus and Robertson. Retrieved 2009-11-03.