Leslie Thomas Fournier was born in Sudbury, Ontario, in 1901 to Tom and Lillian Fournier. The family moved to British Columbia in 1910, settling in Vancouver's West End. Fournier attended elementary school at Lord Roberts and then moved on to King George High School. He continued his studies at the University of British Columbia, earning a B.A. and M.A. in Economics in 1921 and 1923, respectively. Fournier completed his Ph.D. at the University of California, Berkeley, also in Economics, in 1927. Between 1924 and 1937, Fournier was a faculty member in Princeton University's Department of Economics, where he focused primarily on public utility regulation. During his time at Princeton, he consulted for the New Jersey Board of Public Utilities Commissioners. Also, he wrote and published Railway Nationalization in Canada: The Problem of the Canadian National Railways. In 1937, Fournier left Princeton to act as a financial consultant to the U.S. Government's Securities and Exchange Commission and remained there until 1946, when he joined Panhandle Eastern Pipe staff Line Company, acting first as vice-president charge of Economics. Four years later, he was also appointed Treasurer of the company. Leslie Fournier married Dorothy Brenchley on September 12, 1926. They moved to Ridgewood, New Jersey, where they had two daughters, Ann and Jane. Fournier died of a heart attack at his home on July 5, 1961.