John O. was born on September 8th, 1859. John O.'s father was George Gentry and his mother was Charlotte Hull. His paternal grandparents were Samuel Gentry and Abigail Powers. He had a brother and a sister, named Samuel and Abby G.. He was the oldest of the three children. He died at the age of 40 on February 5th, 1900. He was buried in Folsomville Cemetery.