We ARE Mill Valley
Administration
Dr. Gail Holder, Principal
Gail Holder joined USD 232 in 2020 as the principal of Mill Valley High School.
Dr. Holder began her teaching career in 1990 as an English teacher and dance team coach in the Olathe School District. In 2016, Dr. Holder transitioned to the Olathe district office where she worked as the assistant director of teaching and learning for two years. She then transferred to Olathe East High School and served as an assistant principal for two years.
Dr. Holder earned a doctorate from Baker University, an administrative certificate from Pittsburg State, undergraduate and master’s degrees from the University of Kansas, and an associate degree from Kilgore College.
Dr. Holder is committed to the success of ALL students and believes deeply in the importance of a strong and meaningful educational experience.
Mr. Kent Mailen, Associate Principal & Activities Director
Kent Mailen joined USD 232 in 2026 as an associate principal at Mill Valley High School.
Mr. Mailen has been in education since 2006, most recently serving as an assistant principal in Kansas City and Dubai. Before that, Mr. Mailen taught high school social studies and coached boys’ basketball for 14 years in Kansas, Morocco, China, and Paraguay.
Mr. Mailen is working on a Doctorate of Education from University of Missouri-Kansas City, earned a master’s degree from Emporia State University in 2011, and earned a bachelor's degree from Kansas State University in 2006.
Mr. Mailen's wife, Jaclyn, is a high school chemistry and science teacher at Shawnee Mission South High School. They have two children, Elliette and Arno.
Mr. Chase Shumsky, Associate Principal & Athletic Director
Chase Shumsky joined USD 232 in 2026 as the athletic director and associate principal at Mill Valley High School.
Prior to working at Mill Valley, Mr. Shumsky taught for six years as the 6–8 music teacher at Guadalupe Centers Middle School. In addition to his teaching role, Chase held roles such as electives Professional Learning Communities (PLC) lead, electives Continuous Learning coordinator, summer school site coordinator, assistant boys’ basketball coach, and assistant boys’ volleyball coach.
Mr. Shumsky has a Master of Science in Education in Educational Leadership from Northwest Missouri State University. He also has a Bachelor of Music in Music Performance – Saxophone Emphasis and a Bachelor of Music Education – Instrumental Emphasis from the University of Missouri-Kansas City Conservatory.
In 2020, Mr. Shumsky received the Outstanding Beginning Teacher of the Year Award while at Guadalupe Centers Middle School. In 2023, his PLC was awarded PLC of the Year.
Mr. Shumsky married his wife, Jessica, in July of 2026. Outside of work, Mr. Shumsky enjoys staying active through sports or weightlifting, reading a good book, and wrestling with his dog Lollipop.
Ms. Cheyenne Zwahlen, Associate Principal
Cheyenne Zwahlen joined Mill Valley High School in 2026 as an associate principal.
Ms. Zwahlen has been in education since 2009, serving as an elementary teacher, teacher mentor, and most recently as the building coordinator for Mize Elementary.
Ms. Zwahlen holds a Master of Science in Curriculum and Instruction with an emphasis in Mentoring/Instructional Coaching, a Building Leadership License from Baker University for pre-k through 12th grade, and a Bachelor of Arts in Education from Ottawa University.
Ms. Zwahlen firmly believes that every student has the ability to learn and flourish in an environment that promotes belonging, high expectations, and meaningful opportunities. She is committed to empowering educators and students alike by fostering a supportive environment that encourages innovation, continuous improvement, and shared success.