Childhood and Early Life
Zack, born in the town of Gongaga, had childhood dreams of joining SOLDIER to become a 1st Class like the legendary Sephiroth. At the age of thirteen, Zack left Gongaga, without even telling his parents, and joined the Shinra's military forces.
Entering SOLDIER
By October of 0000, he had reached SOLDIER 2nd Class under the tutelage of SOLDIER 1st Class Angeal Hewley. Angeal's words of wisdom and strong sense of honor had a profound effect on Zack, who wanted to be just like his mentor. During his time in SOLDIER, Zack befriended 2nd Class SOLDIER Kunsel, who guided him in the ways of Shinra. Zack works under Director Lazard Deusericus in the 49th Floor of Shinra Headquarters, along with many other SOLDIER members.
War With Genesis
In Crisis Core -Final Fantasy VII-, Zack is first introduced undergoing a digital training session with his mentor Angeal Hewley. Zack successfully completes the mission, but while he is caught off-guard by the victory, is attacked by a virtual form of Sephiroth. Sephiroth overpowers Zack, but Angeal saves him and ends the training. Angeal leaves saying, "To be a hero you need to have dreams...and honor." Despite the debacle in training, Angeal requests to Director Lazard that Zack be promoted to 1st Class. Zack is soon sent on his own mission to Wutai so as to prove his abilities. Though Zack became ecstatic over Angeal's suggestion, he received some interesting news during the briefing: 1st Class SOLDIER Genesis Rhapsodos had deserted Shinra, taking an untold number of 2nd and 3rd Class warriors with him.
Angeal and Zack arrive in Wutai and began their walk to the Fort Tamblin. On the way, Angeal asks Zack if he knows what "dumbapples" are. Zack replies no and learns the origin of the apples and that Angeal was poor growing up. As they wait for a bomb to go off, Zack questions Angeal why he never uses his sword, the Buster Sword, saying it seems wasteful. Angeal simply states that "Use brings about wear, tear and rust, and that's a real waste." The bomb goes off and Zack jumps down and takes out the forces single-handedly. Zack enters a room and is attacked by two anti-soldier monsters. He defeats them before a third falls. Zack attacks it,and believes it to be dead. When he turns his back, the monster uses a backhand slap and sends Zack flying to the wall. Angeal arrives, just in time, and kills the monster using the Buster Sword right before the monster finishes Zack off, and when Zack asks about his sword, Angeal says, "You're a little more important than my sword, but just a little."
While heading back to meet with Lazard, several soldiers attack but Angeal stays behind to deal with them while Zack gets Lazard to safety and heads back to discover Angeal missing. Ifrit appears and battles Zack. Once again, Zack falsely believes he won and gets attacked. Just then, Sephiroth arrives and defeats Ifrit in one blow. A shocked Zack watches Sephiroth identify the bodies as copies of Genesis. Realizing that these were the soldiers that Angeal had last been seen fighting, and that he was nowhere to be seen, Sephiroth comes to the conclusion that Angeal left with his long-time friend, Genesis. Zack, however, refuses to believe that his mentor would ever desert Shinra. Zack soon is given a new mission by Lazard. He is joined by Tseng of the Turks. In Angeal and Genesis's hometown, Banora Village, Zack and Tseng find a grave and Tseng stays to investigate. Zack heads into the village and finds only one person, Angeal's mother, Gillian Hewley. She asks him where Angeal is but Zack says he doesn't know. Zack heads outside and finds an alternate path that leads to a factory. Inside, Genesis appears and taunts Zack and injures Tseng. Angeal arrives and defends Zack, but soon pushes him away. Tseng soon reveals that due to the high number of hostiles, several planes are going to bomb Banora. Zack races to save Gillian but finds her dead on the floor, Angeal standing above her. Thinking Angeal did it, Zack punches him and questions his honor. Genesis arrives and trips Zack, letting Angeal go. Genesis summons Bahamut, which Zack defeats. Zack soon questions Genesis about his honor to which Genesis replies that he has no honor. Sprouting a black angel wing, Genesis flies off. As Zack heads towards a Shinra Helicon with Tseng in it, he watches the bombing of Banora and gets on the Helicopter.
In April 0001, Zack is at Shinra Headquarters when Lazard awards him the title of SOLDIER First Class. Zack is not happy that he attained his dreams so early, and after so many losses. At that moment, Genesis's army attacks Midgar, and Zack has to fight them throughout the city. Along the way, he saves Cissnei, another member of the Turks. Sephiroth and Zack both head to the Sector 5 Reactor to find the rogue Dr. Hollander, who is suspected of working with Genesis. Zack chases Hollander through the Reactor until he runs into Angeal, who says that his goals are world domination and revenge. Sprouting wings, Angeal tells Zack that he is a monster. Zack replies that he is not a monster because he has angel wings, and Angeal questions him on his answer. Not satisfied with his response, Angeal attacks Zack and knocks him back. Refusing to fight his old friend and mentor, Zack refuses to defend himself from Angeal's attack. Angeal then uses magic to knock the platform beneath him away, causing him to fall.
Zack drops through the roof of a church, where Zack meets Aerith Gainsborough. Grateful to her for saving his life (although she insists that she did nothing but say, "Hello-o!"), Zack offers to pay Aerith back with one date. However, Aerith laughs and calls him silly. Zack sees the flowers and is impressed, saying that flowers are rarely seen in Midgar. Zack suggests that Aerith should sell the flowers that grow in the church. Later on, Zack gets his wallet stolen by a child, and would eventually find him, only to find that the child's wallet was eaten by a monster. In generosity, he lets the child keep his wallet in order to buy some medicine, or you can choose to take the wallet back from the monsters. That being done, it happens that the kid had a lot more money in his wallet than in Zack does in his. Zack then buys Aerith the ribbon that she is seen wearing throughout the series.
However, their date is cut short when Zack has to return to the Midgar Plate to defeat Genesis. While on route, Angeal lands and explains that he and Zack must work together. Zack agrees and the two fly off to the Shinra building. Sephiroth explains that Hollander is most likely after Hojo due to Hojo taking over his job. Zack arrives and Genesis does as well as Angeal. Genesis flies out and Angeal grabs Zack and puts him down so that he can face Bahamut Fury while Angeal deals with Genesis. After the battle, Zack sees Angeal and Genesis gone and once again asks himself where he is.
Death
At the end of September (0007), while Zack and Cloud head back towards Midgar, a massive army of Shinra Troops awaits them. Despite Cissnei and Tseng's attempts to save Zack first, the Shinra army attacks. A Shinra sniper attempts to assassinate Cloud, but Zack notices this and tells Cloud to get away, causing the sniper to miss his mark, starting the battle. Zack fights hard against overwhelming odds. However, the enemy is just too many, and despite all of Zack's SOLDIER training (presumably, defeating not all, but most of the army, considering there is apparently only a handful of soldiers left in contrast to the vast amount of enemies facing him earlier), he is defeated. In the original Final Fantasy VII, in the flashback, there are only two Shinra soldiers and one commander, who shoot Zack by surprise. Riddled with bullets, and his Digital Mind Wave destroyed, Zack is barely alive when Cloud awakens and comes to him. Zack hands the Buster Sword to him, like Angeal handed the Buster Sword to Zack four years earlier. He tells Cloud to carry on his dreams, and be his "living legacy".
As Cloud wanders off towards Midgar, Zack looks at the sky as the sun begins emerge and shine, remembering how scared Aerith was of such a beautiful thing. He then sees Angeal descending from the sky, two white wings outstretched, finally a free spirit. Zack says that he wants Angeal's wings too and takes Angeal's outstretched hand, proceeding thus into the Lifestream. As Cloud continues on his journey, Zack tells him to say hi to Aerith for him, and then asks the question "Hey, would you say I became a hero?" echoing his once called "unattainable" dream of becoming a hero.
The combined weight of all this trauma finally makes Cloud snap, and barely conscious, he makes his way to Midgar dragging the Buster Sword behind him. Collapsing in the Sector 7 Station, Cloud is found by Tifa, where he, aided by the Jenova cells he now has in his body, adopts Zack's memories and persona, combining it with an idealized image of himself to create a new personality and history for himself. After the creation of this facade, Cloud truly believes that he was successful in joining SOLDIER, and that he fulfilled Zack's role in the fateful mission to Nibelheim four years before. He believes he has come to Midgar to seek work as a mercenary, just as Zack said he intended to do. In fact, Zack no longer even existed in Cloud's mind; the altered memories placed him in Zack's stead. Realizing something is wrong with Cloud, Tifa convinces him to join her and Barret with AVALANCHE to keep an eye on him. It is on the mission to blow up the Mako Reactor that Cloud performs for AVALANCHE that Crisis Core ends and Final Fantasy VII begins.
