On September 3, 1867, he married Rebecca Medwin Copcutt, a daughter of Yonkers, New York, industrialist John Copcutt (1805–1895) at the historic John Copcutt Mansion. Until his retirement in 1928, Dr. Leale maintained a continuous interest in philanthropic, medical, and scientific projects. Leale was one of the last surviving attendees of Lincoln's assassination upon his death in 1932 at the age of 90.
On September 3, 1867, Dr. Leale married Rebecca Medwin Copcutt, a daughter of John Copcutt (1805–1895), an industrialist from Yonkers, New York, at the historic John Copcutt Mansion. Throughout his career until his retirement in 1928, he remained engaged with philanthropic, medical, and scientific initiatives. Leale was one of the last individuals to witness Lincoln's assassination upon his death in 1932 at the age of 90.