Graham is a tall man with wavy blonde hair that has grown over his green eyes. He dresses in a blue mechanic's outfit with brown gloves. He always carries an oversized monkey wrench, which he uses as his primary weapon.
Graham has an turbulent personality. He has a peculiar tendency to speak frantically, repetitively, and often philosophizes violently —he will lament about his current state of affairs in the most negative way possible, before changing his mood and suddenly viewing the same issue in a contradictory, impossibly optimistic way. It's mostly rambling, though driven by what appears to be frequent bipolar mood swings. Narrative from the books quotes that Graham's mood is only ever either at a scale of 0 or 100 and never in-between.
He tends to do things on a whim, and can be quite reckless. He has an obsession with dismantling things, be it objects or actual people. He hates it when people destroy vehicles he wants to destroy himself, just as much as Ladd hates people who kill those he wanted to kill himself. However Graham doesn't actually kill people - he merely "breaks" them - because killing makes him feel guilty. This is not a sign of mercy as some would think because he can be rather aggressive and capable of doing both serious and permanent damage that can leave people traumatized.
Ladd is his hero, and he worships the man. He will take things on his agenda if it means it'll benefit Ladd, or he thinks it will. For example, he wanted to fight Claire, but realizing that he was weak in comparison, Graham left him for Ladd because he thought they'd be more on level.
Despite his chaotic persona, Graham is actually very intuitive. His knowledge of machinery expands into needless trivia and different ways to incapacitate people with his wrench. He correctly surmised that his second in command, Shaft, had orchestrated the fiasco at Dolce, and was able to detect and block Leeza's chakrams even though she hid in the shadows. Though his plans often go awry, Graham is quick to adapt and is very versatile. He is still very prone to being controlled by the heat of the moment, and his emotions will often override any common sense.
Graham's weapon of choice is a large crescent wrench that he can throw like a boomerang (aiming at proper angles when thrown so that it will come back like a boomerang)...or simply use as a blunt instrument of brute force. He can also use it for impressively delicate feats: he has caught everything from bullets to people's throats inside the wrench's vice, and he can dislocate joints as easily as he can unscrew a bolt. All of this makes him far more unorthodox and unpredictable than Ladd, for it is far more difficult to discern a pattern in his fighting.
It is no exaggeration to claim that Graham is one of the most powerful fighters in the series. He was capable of defeating the Lamia (who had recently crippled some of the Russo's top men, including three-incomplete immortals), kidnapping Chané Laforet (who had gone toe-to-toe with Ladd on the Flying Pussyfoot), and he even briefly held the Rail Tracer in a stalemate. According to Ladd Russo, Graham is much better than he is in a fight—he just refuses to kill his opponents.
His personality often confuses his enemies, who are unequipped to deal with his frequent mood-swings during a fight. It appears that when his mood changes his fighting style adjusts slightly as well.