She was born Florence Mabel Kling above her father's hardware store at 126 South Main Street in Marion, Ohio, on August 15, 1860. Florence was the eldest of three children of Amos Kling, a prominent Marion accountant and businessman of German descent, and Louisa Bouton Kling, whose French Huguenot ancestors had fled religious persecution. Her younger brothers were Clifford, born in 1861, and Vetallis, born in 1856. Florence attended school at Union School beginning in 1866 and studied the classics. Her father prospered as a banker and was a stockholder in the Columbus & Toledo Railroad, President of the Agricultural Society, and member of the school board. Florence developed a passion for horses early in life and participated in several horse races. Her father trained her in several business skills such as banking, real estate, and farm management.