Personality
Bud is an only child, which translated to a deep loneliness. A loneliness he's still trying to fill and what might be at the root of his obsession with super-heroes and joining their ranks. He hides his loneliness by being relentlessly cheerful, even in the face of great danger or situations where such an attitude would be inappropriate. This tends to leads people to think that he's not serious about his endeavors, but nothing could be further from the truth when you look at what he's accomplished.
Background
It was the week of his thirteenth birthday, on a visit from Metropolis to Gotham City with his parents to visit his cousin Bruce Wayne that Bud Kane's life changed forever. While there, his family was assaulted by a gunman as they left a theater and cut through an alley. As his father confronted the gunman and tried to talk him down, Vengeance fell from the shadows above, paired with a bright little birdie at its side. They made short work of the gunman, and a huge impression on young Bud.
Bud took his own stab at crime-fighting. Dressed in a costume reminiscent of Robin's in red, yellow and green, Bud dubbed himself 'Bat-Lad' and began his meager crime-fighting career. While he wasn't terrible at it, and took down a few street-level criminals, he kept getting closer and closer to danger until the Bat came to him and put his foot down: Bat-Lad was done, or Batman would reveal his nocturnal activities to his parents.
So, Bud left the Twin Cities and headed West, to California. There, he trained extensively in gymnastics and martial arts, in addition to his regular training in his sport of choice, tennis. He quickly became expert in all of those, winning several trophies in each, and qualifying for the Olympic Tennis team. He even won silver at the Olympics one year. But he only ever had one goal in mind: returning to his dream life as a crime-fighter.
And now, he's back, with a new costume, a new code name, and the same determined attitude. Criminals, beware the Flamebird!