Charles Rehmann was born on Tuesday, March 20, 1900 in Atlantic City, New Jersey. He was the fourth child of Christian Wilhelm and Ida (Scull) Rehmann.

In the 1900 census, the family were living at 123 Massachusetts Avenue in Atlantic City. The 1910 census shows them living on Park Avenue in Vineland Borough, Cumberland County, New Jersey. For the 1920 census, they resided at 02 West Foundry St., Millville, Cumberland County, NJ. Charles was listed as a machine boy in a glass factory.