Joel Dahl, founder of Dahled Up Construction, is being taken to court in Albany in the US state of Oregon by ex-worker Ryan Coleman.
A lawsuit alleges that Mr Dahl, who offers building jobs to people leaving prison, made the Christian sessions a mandatory condition of employment for his staff.
Court files allege that Coleman is seeking $750,000 in compensation for "mental stress, humiliation, inconvenience and loss of enjoyment of life" his experienced.
The 34-year-old, who is also seeking $50,000 for alleged lost earnings, told Fox News: "I'm Native American and Christianity's just not my thing."
Speaking to National Public Radio, an attorney for Mr Dahl said the requirement to join Bible studies was lawful because staff are paid to attend. He did not dispute the claim that the sessions have been mandatory.
Kent Hickman said: "We believe that this requirement was not illegal.
"These are at-will employees and they were paid to go.
"It was part of their job, so they were expected to attend."
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