Early life (1979-1990)
Blaine is implied to come from a wealthy family. His older brother, Cooper, was very critical and domineering when they were young, and it is implied that Blaine is not very close to his father because of his sexuality. Before moving to Beauxbatons Academy of Magic, Blaine went to a public school where he was constantly bullied because of his sexuality. Just after he came out, he attended a Sadie Hawkins dance with a friend who was the only other openly gay student at his school. While waiting for his friend's dad to pick them up, he and his friend were jumped by three homophobic bullies and were beat mercilessly. Blaine then decided to transfer to Hogwarts because of their zero-tolerance bullying policy and has soon gained a lot more confidence since.
Beauxbatons years (1990-1995)
Hogwarts years (1995-current)
Personality and traits
Originally, Blaine is portrayed as a young man with a confident exterior that often belies his insecurities. He is very composed and shows a lot of self-control, but there are times when he throws himself into situations impulsively, such as serenading another guy in public and subsequently getting him fired or seeking out Burt to give Kurt the "sex talk." There are other times that shows Blaine having a temper, such as when he snapped at Sam in Hold on to Sixteen for rejecting his suggestions. He is increasingly portrayed as someone who approves the idea of "fitting in." While he's not afraid of being openly gay, he still prefers to act socially acceptable and warns Kurt that trying too hard and showing too much can be detrimental, as proven in the episodes Special Education and Prom Queen.
After moving to McKinley in Season Three, Blaine has shown a more needier, attention-seeking side such as the time his older brother, Cooper visited Lima or when Kurt was texting another guy. Despite his flaws, he remains to be a very passionate and caring young man and loves Kurt dearly.
In Season Four, after encouraging Kurt to leave for New York, Blaine finds himself alone and seeks solice in his friends, Sam and Tina. It is in this time that Blaine shows a more campy, fun side to him and loosens up from his composed, reserved self that he held when he was attending Dalton Academy. He has also grown more dramatic, especially due to his stress about senior year, as shown in Season Five when he catches Sam and Tina tongue-kissing whilst locking themselves in the school for the evening and accuses them of ruining the night he had so perfectly planned.
Towards the midpoint of Season Five, after moving to New York, Blaine's reserved, conservative personality starts coming back, especially in "Tested," when he begins emotionally eating and reading porn websites to deal with his insecurities about Kurt taking batter care of himself and having a brand new independence and maturity, which leads to him feeling as though their relationship is suddenly becoming a battlefield between two guys and not liking the way he feels about himself anymore, which he confides in Kurt, in tears.