Murphy is a Democrat and served in the Iowa House after winning a special election in 1989.

Throughout his term in the House, he had worked on numerous issues related to human services, health care, and appropriations.

As House Speaker he has championed a number of Democratic priorities including raising the minimum wage, increasing K-12 teacher salaries to the national average, expanding preschool programs, promoting "green jobs" by encouraging the expansion of Iowa's renewable energy industry, expanding health insurance coverage, and supporting Iowa's veterans.

Murphy lost to Republican nominee and fellow Dubuque resident Rod Blum in the general election on November 4.

[4] Murphy was succeeded in the state house by one of his former pages, Abby Finkenauer, who would go on to unseat Blum in 2018.