Yes, he replaced the late Richard Harris as Dumbledore.
The character, Albus Dumbledore, in "Harry Potter" is gay. The actor, Michael Gambon, is not.
Michael Gambon
Michael Gambon.
Michael Gambon
Michael Gambon plays Albus Dumbledore in all of the Harry Potter movies except for the first two (Dumbledore was played by Richard Harris in those.) and he also played King George V in The King's Speech.
Richard Harris originally played Dumbledore but he died and was replaced by Micheal Gambon in the prisoner of Azkaban.
Michael Gambon, who continued the role until the end of the series.
Yes, Albus Dumbledore, who is played by Michael Gambon, is killed by Severus Snape at the top of the Astronomy Tower.
Michael Gambon is playing Prof. Dumbledore in the new Harry Potter film, Harry Potter and the Half-blood Prince.
He does make a brief appearance or two, yes.
There are two "Michaels" starring in Harry Potter. The first is Michael Gambon who has starred in all of the films as Albus Dumbledore with the exception of Harry Potter and the Philosopher's Sorcerer's Stone and Harry Potter and the Chamber of Secrets. The second is Michael Wildman who played a centaur in Harry Potter and the Order of the Phoenix.
Michael Gambon has acted in over 100 movies and TV series episodes. You can look at this full list as http://www.imdb.com/name/nm0002091/. Just scroll down to the "Filmography" section.