Dr. Leonard Green (Ron Leibman): Rachel's father, a surly, abrasive and rather amoral vascular surgeon; although he is genuinely affectionate and usually good-natured towards his daughter, he is generally a nasty, mean-spirited bully who is quick to insult anyone who, even by accident, irritates him in the slightest way. He takes an instant dislike to his daughter's boyfriend Ross when the latter refers to Green's profession as "a game." Later, when Ross and Rachel conceive a child (Emma), he becomes furious that they're not engaged because he does not want his grandchild to be a and ends up going to Ross' apartment and shouting at him because Rachel (who is afraid of Leonard's anger) lied to him and claimed that Ross refused to ask her to marry him, leading Rachel to eventually clarify the situation for him. However, he is still angry at her and believes love to be insignificant in a marriage. He has a heart attack in "The One Where Joey Speaks French" and is recovering in the hospital when Rachel arrives with Ross, who he once again treated with contempt.