John Maslin was born in October 1828 in Wiltshire, England and immigrated to South Australia in February 1850 with his wife and child on the Agincourt (ship). In 1851 he went to the Bendigo goldfields and made money before returning to South Australia. Maslin went into business with George Agars, Charles Swinden and Matthew Moorhouse and became a joint owner of Saltia, a property near Port Augusta and other properties. Maslin also visited Queensland to assess its potential but returned to South Australia.

He then joined with Robert Barr Smith in the purchase of the Hummocks, Warrakimbo and Koolunga runs before they acquired the Bundaleer property near Jamestown. Maslin eventually acquired full ownership of Bundaleer. Bundaleer had been developed and owned successively by J B Hughes, and C B Fisher and Henry Ayers. Maslin worked at improving the quality of the Merino sheep on the property. In 1898 he divided Bundaleer between his two sons, Frederick and George. George took the northern section, North Bundaleer, which was subsequently acquired by the government for closer settlement.

John Maslin died at Mitcham 16 May 1908 age 80, a man noted for his generosity and philanthropy.