Following the sovietization of Georgia in 1921, he immigrated to the United States, where he was known as Simon Sidamon-Eristoff after his Russified surname and worked as an engineer.
[1] Simon Sidamon-Eristavi was born in Tiflis, a scion of the Georgian noble family of Sidamoni, whose principal branch ran the duchy of Aragvi from 1578 to 1743.
In 1926, Simon Sidamon-Eristavi, then a widower, married, in New York City, his second wife, Anne Tracy (1890–1978), a descendant of John Bigelow, an American diplomat in the mid-19th century.
Constantine's eldest son Simon is a land conservation lawyer and Chairman of the Chesapeake Bay Foundation.
His younger son Andrew was a Republican Party politician in New York and was New Jersey State Treasurer from 2010 to 2015.