Dr. Christensen served as Superintendent of Schools in two Nebraska communities including Bloomfield and North Platte. In 1994, he was appointed to the top post in education as Commissioner of Education and served in this leadership capacity for 14 years. He was the longest seated Commissioner of Education in Nebraska at the time of his retirement in 2008.

He earned his doctorate in education from the University of Nebraska-Lincoln in 1978 and was awarded an Honorary Doctor of Pedagogy from Doane College in 2007. He was recognized as Administrator of the Year(Kansas) in 1980, Superintendent of the Year(Nebraska) in 1990, and National Public Official of the Year by Governing Magazine in 2004. He has received awards from state and national organizations such as the Friend of Education Award from the Nebraska State Education Association, the Distinguished Service Award from the Nebraska Council of School Administrators, the Transformation Leadership Award from the Coalition of Essential Schools, and the Academic Freedom Award by the National Council of Teachers of English. He was recently honored with the Grace Abbott Award by the Nebraska Children and Families Foundation for his leadership in early childhood education.

In 2008, the State Board of Education conferred the title of Emeritus Commissioner of Education. Dr. Christensen is currently Professor of Practice in the Graduate Division of Doane College where he teaches leadership in education for master's degree candidates.