Malett was born on 14 March 1823 in London, the son of John Lewis Mallet and Frances Merivale of Exeter. He died at Bath on 16 February 1890. Mallet's father was given employment in the audit office in 1801 on the influence of Pitt, and Louis Mallet found similar employment in 1839. In 1847 he was transferred to the Board of Trade, and soon was appointed as the private secretary to the president. He worked with Richard cobden on a variety of reciprocity treaties. Mallet had much influence with political leaders, but shunned party politics himself. In 1858 he married Frances Helen Pellew of Exeter; the couple had four sons.
From The Biographical Dictionary of British Economists in Oxford Reference.