Senator Eigel is a United States Air Force military veteran of eight years and has owned a small business in St. Charles County for more than 10 years.

Senator Eigel, who held the rank of Captain while serving in the Air Force, completed assignments in Louisiana, Arizona, and most recently at Whiteman Air Force Base, Missouri. He is a decorated veteran for service overseas in support of Operation Enduring Freedom, as he was awarded commendations for his service in Ashgabat, Turkmenistan.

After leaving the service in 2006, Sen. Eigel purchased St. Louis Skylights, a small residential and commercial remodeling company. Despite the challenges of the economic recession in 2008 and 2009, St. Louis Skylights was renamed to National Skylight Solutions in 2010 as it grew to service all areas of the United States. With permanent locations in Missouri and Illinois, and serving customers in all 50 states, National Skylight Solutions (and affiliates) is one of the fastest growing skylight installation companies in the country.

Senator Eigel is a member of Veterans of Foreign Wars, the National Rifle Association, and is a volunteer for the Missouri Veteran's Retirement Home in North St. Louis County.

Senator Eigel lives in Weldon Spring with his wife, Amanda, and their two children. They are all members of St. Joseph's Catholic Parish in Cottleville, Missouri.