Wanger was born in North Coventry Township, Pennsylvania, the son of Rebecca (Price) and George Wanger. He served as deputy prothonotary of Chester County, Pennsylvania, in 1871. He commenced the study of law at Norristown, Pennsylvania, in 1872. He served as deputy prothonotary of Montgomery County, Pennsylvania from 1873 to 1875. He was admitted to the bar in 1875, and commenced the practice of law in Norristown. He was as an elected burgess of Norristown in 1878. He was a delegate to the 1880 Republican National Convention. He was elected district attorney of Montgomery County in 1880 and again in 1886. He served as chairman of the Montgomery County Republican committee in 1889.