He received an Associate's Degree in music from Utah Valley University. Kirk then served a two-year mission for the Church of Jesus Christ of Latter-Day Saints in the Philippines. After returning, he continued his education and received a Bachelor's Degree in music from Brigham Young University. He subsequently taught music for six years and managed a music teaching studio. He then went on to pursue a law degree at the University of Oklahoma. He began his law career in Oklahoma primarily in Federal Indian Law including tribal business transactions, gaming law, organization and development of tribal policies and procedures, and administrative law. His practice in Oklahoma also included areas of general business and contract law, property management, fair housing, homeowner association and collections.

He returned to Utah to work for the practice established by his father which focuses on property management, fair housing, collections and real property.

In his spare time, he continues to volunteer his time to music and education as a Chairman of the Board for the Suzuki String Institute, Accompanist for the elementary school choir, former Co-Chair for the Brookwood Elementary School Community Council, and Board member for the Utah Valley University Alumni Association. He also formerly served as the government affairs chair for the Utah Apartment Association.

Cullimore currently serves on the Social Services Appropriations Subcommittee, Co-Chairs the Infrastructure & General Government Appropriations Subcommittee, the Business and Labor Standing Committee, the Judiciary, Law Enforcement & Criminal Justice Standing Committee, and the Tax Restructuring and Equalization Task Force.

Senator Cullimore and his wife Heather live in Sandy, Utah with their 6 children. They stay busy with their kids' activities including violin, cello, soccer, etc.