Kearney served seven years on the planning commission for Swarthmore, Pennsylvania before being elected to two terms as mayor.[3] In total, he served the borough for 12 years, focusing on environmental and social issues, including working towards making the borough more pedestrian-friendly.[4]
In 2018, he defeated RepublicanTom McGarrigle in an upset to become state senator and the first Democrat to represent the 26th district since 1978.[5]