J M Browne was born in Launceston in 1830. He was the eldest of the five sons of Archdeacon of Launceston W H Browne (NG2542). Educated in Launceston, he commenced his career in Hobart as a clerk in the firm of Kerr, Bogle and Co. (NG2481). He spend some time in California in the 1850s during the goldrush. Returning to Tasmania, in 1856/7 he was involved in winding up the Launceston operations of Kerr, Bogle, and Co. It is likely that through this work he came into possession of the papers related to this firm as well as to Alexander McNaughtan (NG3668). Brown formed his own merchant company 'Justin Browne and Co.' (initially called Patterson and Browne Co.). This firm was an agent for the P. and O. Steam Navigation Co.'s.;;Browne was a trustee for several large private estates, including Foster's and Butler's. He was the manager for Perpetual Trustees, Executors, and Agency Co. He was Consular-Agent for France, a director of the T.S.N. Co. and Hobart Gas Co., a Chairman of the Chamber of Commerce, a Warden of the Hobart Marine Board, and a Lands Title Commissioner. He was elected a Fellow of the Royal Society of Tasmania in 1867. He was also a Trustee of the Tasmanian Museum and Botanical Gardens, and a member of the Executive Committee of the Hobart Benevolent Society.;;Browne was an avid collector of archival and published material related to Tasmania.;;In 1867, he married Katherine Poulett-Harris. They had four daughters, Caroline, Catherine, Lilian, and Lucy. Browne inherited an estate in Ireland, Ballinvoher, Castle Town Roche, County Cork, which has been in the possession of the family. Browne died aged 59 at his residence, Davey Street, Hobart.