Hiram McCullough was born on September 26, 1813, near Elkton, Maryland.

[1] McCullough pursued an academic course at Elkton Academy and later studied law.

[1] McCullough served in the Maryland Senate from 1845 until 1851,[2] and was an unsuccessful candidate in 1850 for election to the Thirty-second Congress.

He resumed the practice of law and was for many years counsel for the Philadelphia, Wilmington and Baltimore Railroad.

They had two sons, state senator Clinton and Hiram Rudolph McCullough.