Light was born in Carmel, New York in 1855, to Belden Light and Ann (Keenan) Light. He moved with his parents to New Canaan, Connecticut at a young age, and his first job was at a tannery, where he earned money to fund his education. He married Ida M. Lockwood on August 3, 1881.
Light graduated from Chamberlain Institute and Female College in New York (an early coeducational institution). Light was a schoolteacher while being instructed in the law. He passed the Connecticut bar examination in 1883 and commenced a practice in Light settled in South Norwalk, Connecticut, now part of Norwalk.