In 1853 Brereton studied practical mechanics at King's College London, entering the field of civil engineering upon graduating.
Brereton was first employed in Brunel's office in Duke St, London from 1854 to 1855 where he witnessed the building of the SS Great Eastern.
In January 1858 Brereton escaped death twice when his camp at the Sake River was attacked and looted by a band of 500 Bhils, during the unrest associated with the Indian mutiny.
As he gained promotions, Brereton was eventually appointed chief engineer for the Grand Indian Peninsular Railway and undertook to complete the strategic connection across the continent.
Opening the railway from Bombay to Calcutta in March 1870, the Viceroy of India said, "...it may happen that a thousand years hence, Mr. Brereton's ghost may still hover with anxious solicitude over the unbroken piers of the Trowa Viaduct..." In 1871, following a severe drought in California, Brereton was called to San Francisco by William Chapman Ralston, cashier of the Bank of California.
His 1872 pamphlet, Project for English Middle and Yeoman Class Colonies for California, described the productivity of the land and drew attention to the opportunities, including the welcome that would await immigrants.