The lawsuit, filed in federal court in Arizona, alleges that Brian Bailey was fired from his job as a department supervisor at a Flagstaff Home Depot in May 2010 for his periodic absences from work because of his military obligations.
That would be a violation of the Uniformed Services Employment and Reemployment Rights Act of 1994.
Home Depot spokesman Stephen Holmes said the company fired Bailey for legitimate, performance-based reasons unrelated to his military duties. He declined to provide specifics.
"We would never tolerate the termination of one of our military associates for anything other than legitimate reasons unrelated to military service," he said.
Holmes said the retailer is assessing its options about whether to fight the lawsuit.
The lawsuit calls on Home Depot Inc. to declare that firing Bailey violated the law, pay him lost wages and benefits, and hire him again.
The lawsuit alleges that Home Depot management openly expressed their displeasure with Bailey's periodic absences and expressed their desire to fire him because of them.
"The men and women who wear our nation's uniform need to know that they do not have to sacrifice their job at home in order to serve our country," said Thomas Perez, assistant attorney general for the civil rights division.