He worked as a rural Emergency Physician for 14 years until 2012, when he moved his professional home to the URMC division of Palliative Care, where he works with children and adults who have serious illness in hospital, office and home settings. He was named Interim Chief of the Palliative Care Division in 2015. Dr. Horowitz also founded and served as Medical Director of URMC's Adult Cystic Fibrosis Program from 1999 until 2015.