A lighthouse was erected on the wharf at Saint-Jean in 1873 and placed in operation on May 1, 1874. The square, wooden tower stood twenty-three feet tall, cost $3,112, and displayed a white flash every thirty seconds from a revolving, catoptric lighting apparatus made up of two lamps set in twenty-one-inch reflectors. During its first year of operation, the tower was equipped with a lightning conductor and was raised four feet to protect it from ice floes. In the fall of 1875, storms caused significant damage to the wharf, jeopardizing the lighthouse and causing the Department of Marine to help repair the landing to protect the navigational aid.
Twenty-one-year-old Charles Langlois was appointed keeper of the light in 1875 at an annual salary of $300, and he looked after the light until 1896. The lighthouse doubled as a dwelling for the keeper, and an oil house was built nearby on the wharf in 1876.
On January 11, 1877, William Barbour, Inspecting Engineer for the Department of Marine at Quebec, reported on a visit to Saint-Jean Lighthouse to his superior: “In conformity with your orders, I went down to St. John’s Light, took the revolving gear down, and sent it up to Mr. E Chanteloup, Montreal. This gear has never worked well, and will require to be thoroughly overhauled and put in good working order, so as to make one full revolution every minute, and a flash every thirty seconds.” On March 5, 1877, Barbour returned to Saint-Jean to install and regulate the revolving gear, which was found to now function in first-class order.
A skeletal tower replaced the light atop the freight shed in 1969.
Keepers: Joseph Langlois (1874), Charles Langlois (1875 – 1896), Louis Lachance (1896 – 1909), Théophile Pouliot (1909 – 1912), Alf. Laverdière (1912 – 1925).