Eric van der Woodsen
Eric van der Woodsen is the troubled son of Lily van der Woodsen and the younger brother of Serena van der Woodsen.
Eric van der Woodsen attempted suicide and was consequentially a patient at the Ostroff Center, which prompted his sister Serena to return home from boarding school in the first Gossip Girl episode.
He resides with his family and soon to be step family, the Bass', at The New York Palace Hotel and attends St. Jude's School for Boys.
Late in the first season, Dan Humphrey saw Asher Hornsby (who Eric met at Ostroff) and Eric making out publicly in front of St. Jude's. Georgina Sparks then outed Eric in front of Serena and Lily at dinner.
Eric finally decided to come out of the closet at Jenny and Asher's party, confessing to everyone present. He handled the whole thing with dignity, and with pride. He is the only important gay character in the series.