Murnan was born in Parsons, Kansas and raised in Erie, Kansas. After receiving a Bachelor's degree in Elementary Education from Pittsburg State University in 1988, she moved to Wichita, Kansas with her husband, Rob, to teach kindergarten and 1st grade. In 1992, she returned to Pittsburg to pursue a Master's degree in School Administration and grow her family. Beginning in 1995, Murnan served as the first Executive Director of the Family Resource Center. In this role, she worked to collaborate with the Pittsburg community to provide families access to a diverse set of child care services. During her time at The Center, the organization grew from 30 employees and a $300,000 budget to 100 employees and a $3 million budget. Murnan wrote grant applications, managed staff, and led the effort to acquire a new facility. In 2013, Murnan accepted a position as the Director of Student Support Services with Greenbush Southeast Kansas Education Service, where she currently works to help provide in-home services to infants with disabilities, coordinates Medicaid billing for over 1/3 of the school districts in the state, and provides professional development to teachers and administrators.
In 2013, Murnan successfully ran for one of three at-large seats on the Pittsburg City Commission, receiving the most votes of any candidate in the race. As Commissioner, Murnan supported the passage of bonds to fund utility construction for a new state-owned casino in Pittsburg, voted to invest city funds toward the construction of a new track-and-field center at Pittsburg State University, and approved plans to expand parts of Atkinson Municipal Airport. Murnan also criticized then-Governor Sam Brownback's budget decision to delay the planned expansion of a dangerous two-lane stretch of US-69 highway, stating the citizens of Pittsburg "have repeatedly been told this project was going to happen. It's a huge blow to us, we’ve been waiting patiently."
In 2016, Murnan filed to run as a Democrat for the Kansas House of Representatives' 3rd district seat against the Republican incumbent, Representative Chuck Smith, citing that she "felt the state was in a dire circumstance, near bankruptcy and did not resemble the state she remember growing up in." The district was a high-priority target for Kansas Democrats, as Smith had won the swing district from its previous Democratic occupant Julie Menghini by just 114 votes in 2014. Campaigning against unpopular GovernorSam Brownback and Smith's votes in support of his agenda, Murnan emerged victorious by a four-point margin. She was re-elected by a 10-point margin in 2018. During the 2018 Kansas gubernatorial election, Murnan endorsed the eventual nominee, State Senator Laura Kelly, in the Democratic primary. Kelly would go on to defeat Republican Kris Kobach and Independent Greg Orman in the general election, becoming the 48th Governor of Kansas. Murnan spoke at the 2019 Women's March in Pittsburg on January 19.
