Dennis F. Cullinan was the son of Dennis Cullinan (1830-1908) and Catherine Miers (1838-1912). Dennis Sr. was from the Parish of Rathkeale in County Limerick, Ireland.
His career culminated in his position of Executive Officer with the Buffalo Bolt Company of North Tonawanda. He was a well-known Buffalo clubman and prominent figure in business circles throughout Western New York and had been associated with the
Buffalo Bolt Company for 52 years, acquiring considerable wealth in the course of this career. He never married.
Dennis F. Cullinan's nephew, Edmund P. Cullinan (1905-1971) was Chief Deputy Clerk of the U.S. Supreme Court in Washington, D.C. It appears that this branch from Dunkirk, New York did not produce any children and has thus become an extinct
line.