Francis Shanly was born on October 29, 1820, in Stradbally, County Laois, Ireland.

He was a civil engineer and railway contractor. He was tutored in classics, algebra, chemistry, French, and drawing by Dublin’s best masters. In 1836, he immigrated with his family to London, Ontario. Shortly afterwards, he began a career as a civil engineer, following his older brother Walter (1817-1899) into the business of railway building. He began his career preparing surveys for the Great Western Railway in 1846. Then he became an assistant to his brother Walter, who was the resident engineer on the Welland Canal. In 1848, the two brothers went to the United States and were involved in the Northern Railroad in New York and the Union Canal in Pennsylvania. In 1852, Francis became chief assistant to his brother on the Toronto and Guelph Railway, which soon became part of the Grand Trunk Railway. In 1856, he was appointed engineer of the Welland Railway and was also involved in other railways, including The Northern Railway, the Toronto Railway, the Grey and Bruce Railway, the Midland Railway, and the Great Western Railway. In 1868, Francis and Walter were contracted to tunnel the Hoosac Mountain in Massachusetts and completed the project before 1874. In 1875, Francis was appointed City Engineer of Toronto and held this post until 1880, when he resigned to accept the post of Chief Engineer of the Intercolonial Railway. In 1872, he ran for public office for the riding of Toronto Centre but was defeated.

In 1853, he married Louisa Saunders (1836-1910). He died of a heart attack on the overnight train to Ottawa on September 13, 1882.