Physician W. Leonard Ellis was born in St. John, New Brunswick, and received his medical degree from McGill University. While practicing medicine, he served as librarian for the Natural History Society of New Brunswick. Another interest was Freemasonry: he is mentioned several times in various Masonic proceedings during the early decades of the 20th century; in 1912 he was “Grand High Priest” of the New Brunswick arm of the Grand Chapter of Royal Arch Masons of Canada. In 1902 he was appointed chief medical officer for the federal Department of the Interior charged with ensuring, with the help of regional officers, that regulations regarding all immigrants arriving in Canada were obeyed; during the winters when the St. Lawrence River froze, blocking inland travel on the river, he oversaw immigration locally in St. John, New Brunswick. Around 1904 he married Mildred Coleridge Frost; by 1920, the couple had nine children. In addition to these responsibilities, he was secretary of the New Brunswick Medical Society and recording secretary of the St. John Medical Society.