Chomley was the oldest son of Rev. Francis Chomley/Chamley, Rural Dean of County Wicklow and his first wife, Magdalene Hanna. He entered Trinity College, Dublin in Trinity Term 1838 to study law. His interest in China was due to connections of his step mother's father, Richard Griffith M.P. of Millicent House, Clane, co Kildare, who had retired from trading in the East Indies and China in 1786, and other family members.
Business career
Chomley went to the Far East and became the senior partner of the Dent & Co., one of the largest trading firms in the early colonial history of Hong Kong. Lancelot Dent, former senior partner of the Dent & Co. was arrested by the Qing government in Canton in 1839 on opium smuggling charges which helped triggering the First Opium War. Chomley was also appointed to the Legislative Council of Hong Kong in 1861 on the resignation of John Dent, another partner of the Dent & Co. He was the Senior Unofficial Member from 1864 to 1866. He also acted as consul for the Kingdom of Sardinia during the absence of John Dent in 1861. Chomley was one of the founding members of the provisional committee that launched the Hongkong and Shanghai Banking Company. He chaired the provisional committee's first meeting, held on 6 August 1864 and was elected the first chairman of board of the bank in 1865. Dent & Co. went bankrupt in 1867 during the worldwide financial crisis which originated in 1866 in London. They suffered a loss of no less than £200,000 by the malversations of a Portuguese clerk in their employment at Shanghai, who was sentenced to seven years imprisonment. The petition for adjudication of bankruptcy was filed in the Supreme Court of Hong Kong on 29 June 1867. Chomley had to remove his headquarters in Shanghai and sold the Dent Building to the Hong Kong Hotel Co.
Chomley retired to his home, Clermont, Rathnew, Wicklow County after serving as Her Britannic Majesty's Consul in Hong Kong 1868. He lived with his younger unmarried sister, Lucy and died unmarried 14 April 1892. He is buried in Wicklow Church of Ireland Churchyard with a memorial plaque donated by his sister Lucy which reads "of Claremont, co Wicklow and Amoy, China". His youngest half-brother, Charles Albert Chomley had immigrated with his mother Mary and six brothers to Melbourne, and had returned to Ireland on the S.S. Great Britain in 1860. Charles had "learnt office", learning about the China trade with Sir James Turing in Rotterdam, and was travelling with Edward Turing, youngest son of Sir James, when they were both accidentally drowned in the Lake Neuchâtel. Charles was to have joined his brother Francis in Hong Kong to participate in the China trade.