Editing Mark Greene (section)

== Return to the series ==
In 2008, ''ER'' producers announced that Edwards would reprise his role for the series' final season, with Dr. Greene appearing in flashbacks in the episode "Heal Thyself" shedding light on [[Catherine Banfield|Dr. Catherine Banfield]]'s (played by [[Angela Bassett]]) past.

On November 13, 2008, over six years after his exit from the show, Anthony Edwards returned as Dr. Mark Greene. The flashback episode took place in 2002, just months before Greene's death, and revealed an encounter he had with Catherine Banfield, six years before she began working in that same emergency room. He was treating Banfield's son Darryl who had a debilitating disease that turned out to be leukemia. The story appeared to take place at the point in Season 8 when Mark and Elizabeth were reconciling after she learned his tumor had recurred. Greene takes on the mysterious case to save the 5-year-old. He has a run-in with [[Kerry Weaver]] and [[Robert Romano (ER)|Robert Romano]] about putting this case ahead of his chemo treatment which took a toll on him throughout that day. Darryl dies in the ER but it was Greene's heroic actions that triggered Catherine in the present day to help save a young girl from drowning and may have also inspired her to work full-time at County. During their encounter, Cate kept pressing Greene, who told her to stop being a doctor and to start being a mother. Cate gave the same advice to the young girl's mother.

In the season 15 episode ''The Book of Abby'', long-serving nurse Haleh Adams shows the departing [[Abby Lockhart]] a closet wall where all the past doctors and employees have put their locker name tags. Among them, the tag "Greene" can be seen.