He was born at the family farm that is now part of the Thunder Ridge Ski Area on New York State Route 22.
He was also chairman of the Putnam County Republican Committee for several years, which gave him influence over candidates for local office.
Mallory Stephens was a shrewd businessman whose interests included the 525-acre (2.12 km2) Stephens homestead farm, which he sold in 1956 to the business group that created the Birch Hill Game Farm there.
The historic Little Red Schoolhouse in Patterson was also located on the Stephens farm,[1] where his wife taught and his daughter Alice attended.
He was also an officer of the Maust, Coal, and Coke Corporation, an officer of the Modern Industrial Bank alongside Channing H. Tobias, and the Knickerbocker Associates, a real estate and insurance firm.