From Fan History Wiki
Zack features long, blonde hair, a mustacheless goatee, and the look of a street tough. He stands about 5' 9" tall. Zack wears a pair of blue jeans, a white T-shirt, green overshirt, and usually wears a green beanie cap, similar to Meg's, though there have been whole episodes and drawings where he is not wearing his hat.
Zack is a funny man. He rarely, if ever, avoids making digs at Peter and the rest of the family. He cares for his wife, Meg, deeply, and despises it when people make fun of her. Zack seems to have below average intelligence, and is often at odds with Peter to see who is smarter. Zack can also not be dissuaded from bad ideas, simply on the basis that it could be "cool". he has set himself on fire, broken his legs, and almost been killed several times because of these stunts.
Two years before the story started, Zack worked in a Burger King, but he got fired because of Chris' fault.
Zack then began to work at a 7/11 in East Quahog, a bad neighbourhood that is ridden with kidnappers and criminals. He quit his job after worrying Meg in a gunfight. Zack hated working at the 7/11, and expressed distaste to the low pay, annoying boss, and getting shot on a daily basis.
After Zack quit his job, he opened an Auto Shop called Murdock's Auto. He made reasonable money, and enjoyed working there. This shop was burned down, however, when Peter was left in charge to run it.
After losing his auto shop, Zack began to work at the Pawtucket Brewery with Peter. However, after some months, he finally got tired of working there with Peter, and used his savings to open a pizza parlor along with Meg.
He currently runs along with Meg said pizza parlor named Murdock's Pizza.
The Griffin Family
Due to his mistreatment of Meg, dieregard for practically everybody and obfuscating stupitidy, Zack doesn't have a good relationship with his father in law. They're usually arguing over the aforementioned reasons, and even resorting to physical violence in some instances. However, Zack sometimes showed to be fond of him regarding of his antics. It turned out this animosity was deeper than they expected, when Zack's ancestor (a Native American chief) was overthrown and humiliated by one of Peter's ancestors (probably Griffin Peterson).
Zack has a better relationship with Lois than with Peter, mostly because Lois is usually more closer to earth and sensitive. Still, Zack is bitter towards her when she joins Peter in the Meg bashing or her lack of respect and empathy towards Meg.
Being his wife, Zack professes a deep love for Meg. He always defends her from others when they insult her and comforts her when she's sad or depressed. However, their relationship isn't free of discussions and fights, although in the end they make peace with each other. However, whenever Zack loses (temporary) Meg's love, he will do whatever it takes to win her heart back, and tends to get depressed whenever it seems that he has lost her for sure.
Zack's initially hated Chris because he made him lost his job at the Burger King two years before the story's begining, although now he is in good terms with him.
Zack's relationship with Brian is almost nonexistent, althogh they seems to be in good terms with each other as well.
Zack doesn't like Stewie too much, and has expressed his dislike for him a few times. The reason of this is Stewie's mean behaviour towards practically everybody, and the fact that Lois, instead of punish him, is constantly pampering him.
Despite they don't see each other too often, Zack has a good relationship with his mom Valarie.
Jillian is Zack's half sister. Although they're both fond of each other, Zack is usually irritated by her stupidity and low intelligence.
Despite Cody initially professed a deep hatred for Zack, Zack always wanted to have the father-son relationship he never had with his father, and never gave up with Cody. After a camp trip, Cody accepted Zack as his father and he's now more open towards him and his new family.
Zack shares a brother-like relationship with his cousin Jack, and, in his own words, he said that Jack is a "pretty cool guy".
Zack always had a bad relationship with his adoptive father, mostly due to the mistreatment he got from him, and his mean behaviour towards everybody. Whenever Zacks talk about him, he usually says how he never taught him anything and was constantly neglected. When Frank passed away, Zack didn't even drop a single tear for him, and was even happy to know that he was out of his life forever.
Zack's relationship with Lucifer started out pretty rocky, due to Lucifer's plans to turn Meg into his demonic bride. Since their first encounter, Lucifer tried to mess with Zack's life (as the well as the rest of his family) as much as he could, like filling their home with ghosts.
However, after Zack found out that Lucifer was his biological father, he's now in better terms with him.