William Morgan was born in Wilshamstead, Bedfordshire, England, the son of George Morgan, a farmer, and his wife Sarah, née Horne. Morgan emigrated to South Australia, arriving in Port Adelaide on 13 February 1849. Initially he worked on land near the Murray River, his life was saved by an Indigenous Australian named Ranembe, whose name Morgan gave later to one of his sons. Then Morgan worked for Boord Brothers grocers; and at the beginning of 1852 he went to the Victorian gold rush. He had modest success, returned to Adelaide, and with a brother he purchased the Boord's business, establishing William Morgan & Co. and made it a successful enterprise. In 1865 he became a founder of the Bank of Adelaide. He founded, with Charles Hawkes Todd Connor and William Dening Glyde the firm of Morgan, Connor & Glyde, wheat and flour merchants of 43 King William Street.

Morgan was elected to the South Australian Legislative Council in August 1867, and was chief secretary in the second James Boucaut government from June 1875 to March 1876. He was chief secretary again in the fourth Boucaut ministry from October 1877 to September 1878, and when Boucaut became a judge, Morgan reconstructed the ministry and on 27 September 1878 became premier and chief secretary. This ministry was in office for nearly three years but it did not have an easy passage. One important measure passed was that providing deep drainage for Adelaide, the first city in Australia to have a proper sewerage system. A public trustee act was passed, and there was some railway extension, but other bills were rejected by the council. William Morgan was born in Wilshamstead, Bedfordshire, England, the son of George Morgan, a farmer, and his wife Sarah, née Horne. Morgan emigrated to South Australia, arriving in Port Adelaide on 13 February 1849. Initially he worked on land near the Murray River, his life was saved by an Indigenous Australian named Ranembe, whose name Morgan gave later to one of his sons. Then Morgan worked for Boord Brothers grocers; and at the beginning of 1852 he went to the Victorian gold rush. He had modest success, returned to Adelaide, and with a brother he purchased the Boord's business, establishing William Morgan & Co. and made it a successful enterprise. In 1865 he became a founder of the Bank of Adelaide. He founded, with Charles Hawkes Todd Connor and William Dening Glyde the firm of Morgan, Connor & Glyde, wheat and flour merchants of 43 King William Street.