Dennis spent much of his childhood in Clovis, growing up the son of an Air Force officer stationed at Cannon AFB.
In 1995, he received a teaching degree from Eastern NM University in Portales and continued his studies in the Washington, DC, area-- earning his master's degree while working for US Senator Pete Domenici (R) on Capitol Hill. He returned home to serve as a Field Representative for US Rep. Bill Redmond (R) in Roosevelt, Curry, Quay, Harding, Union, and Colfax Counties.
He joined the Texico Municipal Schools faculty in 1999 and spent more than eight years there, teaching English and math and coaching baseball and volleyball. In 2007, he accepted a position with the Tucumcari Public Schools as assistant superintendent. It was there that he met Rochelle Hodge, a Tucumcari native, who became his wife in June 2008. The couple now live in Logan, where he serves as Superintendent of the Logan Municipal Schools. He and Rochelle have two daughters, Bethany and Addison, and one son, Braden.
Dennis first sought elective office in 2004, when he was elected to a 4-year term on the Public Education Commission (formerly the NM State Board of Education). He served as the Commission's chairman for 2 years. Then, in 2008, he was elected State Representative for District 67 in northeastern New Mexico and was subsequently re-elected in 2010, 2012, 2014, and 2016.
Dennis currently serves on the House Education Committee, the House State Government, Indian, & Veterans Affairs Committee, and the House Rules & Order of Business Committee. During the interim period between legislative sessions, he serves on the Legislative Education Study Committee (LESC), the Military & Veterans Affairs Committee, the Mortgage Finance Authority Oversight Committee, and the Public School Capital Outlay Oversight Task Force.