John William Hopkins was born on September 19, 1825, in Liverpool, England.

He studied architecture in England. In 1852, he moved to Montreal where he created a firm with architects James Nelson and Frederick Lawford (Hopkins, Lawford and Nelson, architects). In 1860, he began to practise on his own. He designed the former Customs Building at Pointe-à-Callière (1863) and the Crystal Palace on Victoria Street (1866), both now demolished. In 1869, he joined forces with architect Daniel B. Wily (Hopkins and Wily). Together they designed the Shaw Building (1869), the Exchange-Bank Building (1874), and the Art Association of Montreal's art gallery, which was to become the Montreal Museum of Fine Arts. In 1879, Hopkins' son, Edward C., joined the company and they remained partners until 1896. Their plans included the Waddell Building (1884) and the Montreal-Street-Railway Building (1893-1895). Hopkins was the first president of the Association des Architectes de la Province de Québec in 1890.

In 1852, he married Margaret Elizabeth Tilley. He died on December 11, 1905, in Montreal, Quebec.

Horace (Quintus Horatius Flaccus); b. 8 Dec. 65 B.C.; d. 27 Nov. 8 B.C.