Michael Jon 'Booster' Carter was born in Gotham city in the 25th century, two minutes before his twin sister Michelle. When he was four, his father Jonar--a compulsive gambler--lost everything and abandoned his family, leaving them in poverty to live in a Gotham slum. A gifted athlete, Michael earned a football scholarship for Gotham University where he became the finest college quarterback in the nation. Pro scouts fought for the right to sign him when he graduated, promising money and fame. He would finally be able to support his mother and sister.
When his mother needed a delicate operation to save her life, Michael began betting on the games he was playing in to raise the money, although he never told her nor his sister where the money really came from. Feeling buoyed by his success, he tracked down his father, wanting to bring him back into the family. He found that Jonar still had the gambling bug and was in trouble with loansharks who had already cut his eye out for being unable to pay them back. He guilted Michael into throwing a game, and the officials finally caught on to Michael's illicit dealings. Expelled from Gotham University, banned from college athletics and shunned by the pros, his football career was dead. His mother and sister were devastated; they were still traumatized by what Jonar had done to the family, and it seemed as if Michael had followed in his father's footsteps.
Feeling that he could never expect forgiveness, Michael left Gotham and drifted until he found employment in Metropolis as a night watchman and janitor at the Metropolis Space Museum. Mopping up the Hall of Heroes at night made him reflect on his ruined life. Seeing the love and enthusiasm people, especially children, had for the heroes of the past stirred his interest. He enrolled in Metropolis University, specializing in the history of superheroes from the twentieth and twenty-first century.
Rip Hunter's Time Machine in the museum gave him ideas; perhaps he could travel back in time, to redeem himself as a superhero in the 21st century. And if athletes could do endorsements, why couldn't superheroes? Stealing items from the Hall of Heroes display, Booster was briefly thwarted by Skeets, a museum docent and security droid. Booster deactivated Skeets and took it with him, leaping into the Time Machine. With his stolen technology, Booster was able to outfit himself in a brightly colored power suit modeled after the heroes of the 21st century. Intending to take on the codename 'Goldstar', Michael instead fumbled by referring to his football nickname first and thus ended up with the name 'Booster Gold'.
Well-intentioned and benevolent, Booster Gold honestly does want to make the world better and safer. He just has a deep-seated need for adulation and fame, not to mention money, due to the hardships and failures in his past. He has had some minor success with his company, Goldstar Inc., which exists solely to promote Booster in every possible venue. His initial forays into the realm of crimefighting, however, were not always so efficacious. Over-eager to provide ideal photo-ops in battle, Booster can get distracted from using practical tactics.
Being a reserve (very much in reserve) member of the Justice League, Booster has occasionally managed to help more high-profile heroes with world-threatening issues. Not that they always notice. Leave it to Mordru to be a huge limelight-stealer. No one seems aware that Booster Gold is completely capable of saving the world from things like portable black holes, if he's given at least four or five chances and a running start at it.
A cursory glance at Booster Gold leads people to believe he is shallow, selfish, greedy, arrogant and dim-witted. There are germs of truth in these accusations, but it is not the whole story.
Booster certainly does seek out ways to make money. He grew up in poverty, struggling to get by in a tiny slum apartment with his mother and twin sister, abandoned by his father. When you huddle in a run-down hovel, hungry and menaced by vermin, money is a beacon that promises to lead you to a better life. Booster has spent enough of his life wanting for things he could not have, he is determined to get a piece of what he has been missing.
Having made foolish choices that ruined his opportunity to be a football star, and feeling that he could never possibly be forgiven by his mother and sister for this, Booster also craves acceptance and adulation. In the back of his mind he believes this might ease the pain he feels from disappointing the two most important people in his life. He has seen how people admire and adore superheroes, and while it would be a hollow replacement for what he lost with his family, it is better than being alone.
Despite the glory-hounding, Booster really does have a heart of gold. He wants to be a hero and he wants to help people and save lives. He is also a loyal and devoted friend and would not hesitate to leap in and sacrifice himself to save lives.
But it helps a little to keep most of this hidden, and most people at further than arm's length. It's better to have fun and a laugh and avoid reflecting on the sad things in life. Especially better to not have people expect too much of you, so you won't disappoint them when you fail. Who wants to be dark and grim? There are other people better suited to that niche.