Beekman was born on August 8, 1733. He was the youngest of six children born to Debora ( Hansen) Beekman and Jacob Beekman (1685–1739), an Albany businessman and blacksmith. His sister, Debora Beekman, married
Gerrit Staats. His paternal grandparents were Johannes Beekman, who was married to Machtel (
Schermerhorn) Beekman. His aunt, Maritje "Mary" Beekman, was the wife of Arnout Schermerhorn (grandparents of merchant
Peter Schermerhorn and great-grandparents of
Abraham Schermerhorn). ==Career==