Metzger was born in Bedford, Pennsylvania on December 29, 1880. He was of son of American Civil War veteran Captain Sol Metzger and his wife Margaret (Andrews) Metzger. He was one of six children with three brothers and two sisters. Growing up in Bedford he attended Bedford Public Schools and the Bedford Academy before going to Phillips-Andover Academy in Andover, Massachusetts. He graduated from Phillips-Andover Academy in 1899 where he was a member of the track team as a member of the quarter mile relay team.