Browne was born in Northfield, Vermont. When the Civil War erupted in 1861, he enlisted as a private in Company C of the 15th Vermont Infantry at Berlin, Vermont. He mustered out of the Union Army in August 1863. Soon afterward, he began working as the camp photographer of the 5th Michigan Cavalry, staying with them in their winter encampment at Stevensburg, Virginia. He took some of the earliest portrait photographs of George Armstrong Custer, commander of the Michigan Brigade, after that officer's promotion to Brigadier General.