Jet Black was born on the planet Ganymede in 2035. While on the planet, he joined the ISSP (Intra Solar System Police) and became known as Black Dog due to his unwillingness to give up and his constant hard work. He is tall and muscular, mostly using brute force during battle unlike Spike who is more skilled in combat. Just like most of the other members of the Bebop, Jet has a dark past that catches up to him during the course of the series. While he was working with the ISSP, he went on a mission with his partner Fad to capture Udai Taxim. Fad betrayed Jet on the mission, which caused Jet to lose his arm after Udai cut it off.
He later quit the ISSP and got a cybernetic arm to replace the one he lost. Even though he left the ISSP, he still seems to keep a close contact with them as seen in the series where Jet contacts his old friend Bob to get more intel on bounties.
Later in the series, Jet learns that a ISSP prison ship was taken over by the prisoners being transported inside and the leader of the prisoners is Udai Taxim, the man that cut he arm off. He decides to go help out to settle his past, but find out that his partner during the mission is Fad, his former friend that betrayed him on the same mission he lost his arm during. At first, Jet doesn't want to go on the mission with Fad, but then decides to give him one more chance. Then head to the ship and confront Udai, when it is revealed that Fad is in alliance with him and has betrayed Jet again. Fad then kills Udai since he no longer needed him and then aims the gun over to Jet. He tells Jet that he will shot him (he doesn't have any bullets in the gun, thus he is bluffing). Jet shoots Fad in the leg and then is forced to kill his former partner.
Another past event that haunts Jet is his former relationship with a girl named Alisa. They both ran a bar together after Jet left the ISSP, but Alisa thought he was too overprotective of her and never allowed her to do much, so she left him. This caused Jet to finally snap and left Ganymede to become a cowboy (bounty hunter). He bought a large fishing boat and added bigger engines to it to allow it to fly in space. He then named it the Bebop as he was a fan of that type of jazz music and set off to look for work when he ran into Spike and they became partners. Even after all this, Jet still had the pain of Alisa leaving him on his mind, but it was put to rest after he found a bounty on a man named Rhint, who was Ganymede.
Jet wasn't sure if he wanted to pursue the bounty as he put so much work into leaving Ganymede and didn't really want to return, but did anyway as the crew needed the money from the bounty. While searching for Rhint, Jet went to Alisa's bar and found her there. He talked to her for awhile and asks her why she left him. She explained that he was too controlling over her and she wanted to be free. Just then, Rhint walks in and is revealed as Alisa's boyfriend. Jet leaves as he doesn't know it is Rhint and returns to the Bebop. Spike later tells him that Alisa's boyfriend is Rhint and Jet tells Spike that he will handle it alone. Alisa and Rhint attempt to escape on a boat to live a new life, but Jet stops them and crashes their boat on the shore. Alisa pulls a gun
on Jet and asks him if he is doing this as revenge to her leaving him. He claims that it isn't that and it is because Rhint is a murderer and must be turned in. Alisa then gives up when the cops arrive to arrest Rhint and Jet then departs, but not before throwing a pocket watch he had receieved from Alisa long ago into the water.
On both accounts which lead Jet to confront his past, he always took the forgiving path out, deciding that his past is his past, it isn't worth going into or trying to get revenge. This is the complete opposite of Spike, who decides to charge head on into his past during the end of the series. Another difference between Jet and Spike is that Jet is very hard working and shows that he cares for others, while Spike is lazy and always trys to hide his feelings within.
During the serie finale of the show, Jet is shot after the Red Dragon attack Spike at a bar. Spike feel guilty about the accident and Jet's injury may be one of the reasons he decides to confront Vicious, to make sure that none of his friends are put in harms way because of his actions and his past. Jet trys to convince him to give up on his past and not to go face Vicious, but Spike eventually gets him to understand that he can't just give up on his past like Jet did and that he must face it or him and everyone he cares for will die. Spike then leaves and Jet is left sitting by himself, wondering if he will ever see Spike again.
Jet is the owner and pilot of the Bebop, but he also has his own custom ship
as well known as the Hammerhead. It looks to be a smaller fishing ship that was given weapons and more engines by Jet. It also has a mechanical arm that uses a harpoon as its weapon.