Zachary was raised in the Comstock Family Manor, a large mansion in the outskirts of Vancouver, Canada, along with his brothers, half-brother and father; his mother passed away in 1991. While at Ilvermorny, Zachary was quite popular; he was a confident, handsome student who was proficient at Quidditch and had a knack for defence, co-leading Ilvermorny's Duelling Club. He had many friends, though no friend was ever closer than his half-brother, Connor. During his fourth year, he began dating Julia Doyle, a transfer student from one of the few independent wizarding schools in Canada. After graduation, Zachary proposed to Julia, though the two opted for a long engagement, and after a semester at the European Magical University, they decided to tour the world.
Zachary and Julia's wedding was set for the summer of 2004, though that day never came; tragedy struck when a Portkey set to take wizards from Canada to France for Connor's wedding vanished, taking with it all twenty-three witches and wizards who took it, including Julia and several members of Zachary's family. Zachary was crushed and began drinking excessively as a way to alleviate the pain. He coped with the loss by confiding in his only remaining brother, John, as well as spending time with Julia's younger sister, Ruby. The two quickly found solace in one-another, being each other's emotional and sexual healing from the painful loss of many members of their family.
Zachary and Ruby married some years after, with Ruby giving birth to two children; Connor Jonathan Comstock, in memory of his deceased half-brother, and Julia Abigail Comstock, in memory of Julia. Zachary continued on his career track of being a Hit Wizard, becoming one of the Auror department's finest wizards, but was kicked out for being . Zachary and Ruby moved into a house they built in St. Catharines, Ontario along with John and his family.