Horatio Oliver Ladd was born on August 31, 1839, in Hallowell, Maine, to Samuel and Caroline Ladd. His father earned a living as a merchant. He grew up and attended school in Farmington, Maine, and he graduated from Bowdoin College in 1859. He spent the next two years working as principal of Farmington Academy. He earned his Master’s degree from Bowdoin in 1862, and he graduated from Yale Divinity School the following year.
He married Harriet Vaughan around 1863, and they had at least four children: Lilly, born around 1865; Julia, born around 1867; Harry, born around 1869; and Maynard, born around 1873. He worked as a minister in Connecticut, Michigan, Massachusetts, and New York. By 1870, he owned $2,000 of real estate and $1,000 of personal property. He helped found the University of New Mexico in Santa Fe in 1881, and he served as the university’s first president. He died in Brookline, Massachusetts, on February 16, 1932.