He emigrated to the United States in 1846 with his mother Judith Eidlitz after the death of his father Abraham.
Having served a four-year apprenticeship, he set up in business for himself in 1852 - the year of his marriage - and founded the construction firm, Marc Eidlitz & Son in New York City.
In New York, he was President of the Building Trades' Club and of the Germanic Savings Bank.
Marc converted to Catholicism and kept close ties to the German immigrant community, becoming president of Germania Bank in 1888.
Kathryn Holliday, Leopold Eidlitz: Architecture and Idealism in the Gilded Age (New York: W.W. Norton, 2008)