Mayer's occupation is as a bookie (bookmaker) in the human world, running numbers on everything from sports to natural disasters, with a gambling establishment open to humans where he feeds off their luck. He kidnapped Bo to have her investigate how a human customer, Roger, was able to dupe him. Mayer had been feeding off him for years and had drained him of all his luck. In exchange for this, his niece Cassie, an Oracle, would read Bo's fate to find out more about her mother (Dead Lucky).
Bo and Kenzi discovered that it was his nephew, Seymour, who was the culprit behind it. Mayer told Bo that Seymour was family and he would "put him somewhere safe." After Bo agreed to keep Mayer's secret about what his nephew had done, he let her consult with his niece.
It's not Mayer himself that is influential in Fae politics, but, rather, his niece Cassie as an oracle.
Mayer was shown removing the luck of a Fae by touching Bo lightly on her shoulder, causing her to trip and fall backwards as she walked away after initially refusing to help him.
Mayer is one of the more sympathetic Dark Fae characters, being jovial and jocular at most times. He is also very much unwilling to fight physically (though this may be due to the fact he's a Luck Fae and wants to keep a good image).
Although he is unethical in his dealings with humans, he is fair in his dealings with Bo and shows concern for her when she leaves to confront Vex.
Mayer's strong Yiddish  accent indicates that he is most likely Jewish from Central Europe.
"Bad peace is better than good war." – to Bo (Dead Lucky)