Lewis was born in or near Cleveland, Lucas County, Iowa (distinct from the present township of Cleveland in Davis County), to Thomas H. Lewis and Ann (Watkins) Lewis, immigrants from Llangurig, Wales. Cleveland was a company town, built around a coal mine developed one mile east of the town of Lucas. His mother and grandparents were members of the Reorganized Church of Jesus Christ of Latter Day Saints (RLDS), and the boy was raised in the church's views regarding alcohol and sexual propriety, as well as a just social order that favored the poor. While his maternal grandfather was an RLDS pastor and Lewis periodically donated to his local RLDS church for the rest of his life, there is no definite evidence that he formally joined the Midwestern Mormon denomination.