Augustus had untidy black, spiky hair, with buck teeth and overall pale-brown skin. He had stormy gray eyes (though when he was younger, they were darker), but they always flashed to red when he got angry. He had a slightly crooked nose, and he was about 4'7. He had glasses that were rather big for him, but he could see perfectly fine. These glasses were only for reading, though.
Augustus was a generally nice person but preferred being quiet and overall respectful. He was brave, and he did not flinch at something most people feared. He was incredibly nice, and he had friends with who he was fiercely loyal. However, he did not believe in the magic world because of his Muggle status until he got the letter from Hogwarts himself, hinting that he does not trust things easily until he is face to face with them. He was incredibly courageous as well and would give up his life for the people he cared for most. He was very respectful to all individuals, and even helped others when others needed it.
Augustus was born to Muggle parents in Oxford, England. He had a little sister a year later, who was also magic, but she was too young to attend Hogwarts until she was 11.
His parents were "aristocrats", or well-born. They were born in Greece but initially moved to London since Augustus's father got a job overboard.
He lived in a 7-story house, but he shared a room with his sister.

Augustus is of Greek and Irish descent, but his parents with born in South Korea,
His parents were relatively rich, even by wizard standards. While his parents generally cared for him and his sister, they never could pay attention to them because of their busy work. They were under the care of a caretaker, with who Augustus was fairly close.
His parents were also incredibly strict since Augustus was going to be the heir of his father's company. While his parents did allow him to have friends (under strict supervision) and didn't have a bunch of bodyguards follow their kids around all the time, they always pressured him to do well in school. His parents did deep down, only want the best for him.
His mother, Beatrice Western, had a distant ancestor who was a Squib and had married a Muggle (which is the basic formula of a muggle-born). As such, he was the result. He had no account of this, and his parents had hidden the story from him being ashamed of the matriarch's (mom's side) background.
When he was about 8, his parents died in a car crash, leaving a permanent scar of trauma in his life, as he was with them in the car that night. He still blamed himself for their deaths, but never thankfully, had depression because of it.
He and his sister were put under the care of their grandmother. They were left with a huge inheritance from their parents, but only when Augustus comes of age.
As it turned out, his mother's great-great-great ancestor (his 3x great aunt) had been a Squib and married a muggle, presumably.
His grandmother was proud of him but initially was frightened for his safety. Because she was a muggle, she did not know about Hogwarts at all or anything to do with it, so she was concerned about rules and all.
He was bullied at school but did make friends.
He attended a private Muggle school, which was an all-boys school.
He was very protective over his friends and his sister and overall cared for anyone. He always wanted to prove himself. He did relatively well in school, but he did have trouble with various branches of math, such as repeated addition or algebra.
At some point, at a dinner party his parents hosted for his 7th birthday, he started looking at every one since he was nervous. He made eye contact with a distant aunt of his, who was talking about how "different" Augustus was, and plainly sharing a story about him he was uncomfortable about, and then, without meaning to, the aunt turned into a lizard and climbed onto the expensive antique table. The people at the party saw it and simply began to scream and one fainted. This incident still made tears of laughter come into Augustus's eyes.