When John Henry Agan was born on 12 May 1858, in Indiana, United States, his father, Christian Bingaman Agan, was 27 and his mother, Louisa May, was 21. He married Sarah Kathern Lefever on 5 October 1880, in Lucas, Iowa, United States. They were the parents of at least 4 sons and 3 daughters. He lived in Rose Hill, Johnson, Missouri, United States in 1920 and Kansas City, Wyandotte, Kansas, United States in 1930. He died on 28 February 1949, in Wyandotte, Kansas, United States, at the age of 90.