Dr. Mark Greene is a fictional character from the television series ER, which aired from 1994 to 2009. He is portrayed by actor Anthony Edwards and serves as an attending physician in the emergency room of Chicago's County General Hospital. Dr. Greene is known for his dedication to patient care and his leadership skills, often mentoring younger doctors. Throughout the series, Dr. Greene faces various personal and professional challenges, including balancing his demanding job with family life. His character evolves over the seasons, dealing with issues such as divorce and cancer, which adds depth to his role in the show.