 Schwan was born in Wulsdorf, now a neighborhood in the city of Bremerhaven, Bremen, Germany, but in 1841 part of the Kingdom of Hanover, and received his initial schooling in Germany.He immigrated to the United States in 1857, arriving at New York on 30 May 1857 on the sailing ship Ariel.On 12 June 1857, Schwan enlisted as a Private in the Regular Army, four weeks before his 16th birthday, and served in the 10th U.S. Infantry.