Jakeem Johnny Williams is from Keystone City, Kansas. His mother left his father when she was pregnant, never having told him and leaving him unaware of Jakeem's existence. His mom died of cancer when he was young, and he found himself orphaned. Jakeem went to live with his Aunt Lashawn. To survive growing up he became a protective cursing boy.
Jakeem got the Thunderbolt from Jay Garrick by mistake, when the speedster gave him the pen the genie was being kept in. Johnny Thunder, suffering from Alzheimer's disease, started to loose control of the Thunderbolt so he put it in a pen and eventually gave the pen to Jay, not knowing that was the pen that contained Yz.
Jakeem John Williams first appeared in The Flash #134.
Attack From the Fifth Dimension
A genie from the fifth dimension was given freedom by Triumph, who was given younger age and his powers back. The genie then started terrorizing a city. This is when Jakeem finds out the pen has a genie in it. But Jakeem thinks the genie is the devil. Jakeem, with the Justice Society of America and Justice League, figures out the genie is a fifth-dimensional being. And it is controlled by saying its name Yz which backwards is pronounced "so cool". Captain Marvel helped with merging the two genies together which made a purple Thunderbolt. This is controlled by saying "so cool".
Justice Society of America
Jakeem then joins the JSA, not wanting to but then comes around. Grundy being affected by Joker's laughing gas attacks the JSA headquarters but the only ones there are Stargirl and Jakeem. Grundy steals Jakeem's pen with the Thunderbolt. Here Jakeem tells Stargirl he wants to get the pen back not because it's the Thunderbolt but because it's his friend. After this fight, Jakeem half wishing half talking out loud wished that Johnny Thunder would get better. It then was revealed that Johnny was completely cured of Alzheimer. He made his way to the Brownstone to see everybody and to talk to Jakeem personally. When the two of them have some privacy, Johnny insults Jakeem saying that it was a mistake he got the pen and a stupid brat like him had no right to it. He then demands the pen. When Jakeem sadly gives it back, Johnny immediately uses it to make himself young and whole in body and then dramatically reveals that he is the Ultra-Humanite in control of Johnny's body! In the course of six months, he has completely taken over the world and every bodies mind. Jakeem was one of the few not affected (probably due to previously owning the pen) and the surviving heroes and villains managed to stop the Ultra-Humanite at the cost of Johnny's body. Johnny survives because the Thunderbolt merged with him, so Johnny now has his powers. It is not properly explained whether the Thunderbolt died to save Johnny or if they merged into a new being because both are seen at different times in the JSA series.
Jakeem and Johnny/Thunderbolt become really tight friends after this.
Jakeem stays at home on the weekdays to go to school. With the Thunderbolt's help Jakeem meets his biological father. He speaks to him without telling him he's his son. They get along very well until Jakeem sees his father started a family. Jakeem fears he will destroy their family so he doesn't tell him that he is his son.
During the time where the Spectre goes mad and wants to destroy all magic he puts Jakeem into the pen leading to the 5th dimension. Here Qwsp controls Jakeem, and tricks him into destroying the 5th dimension. The Thunderbolt gets the JSA and some of his friends to help. With their help Jakeem is cured.
Tenth Age of Magic
In this new age of magic, whatever Jakeem wishes for it is taken from somewhere else. When a fire happened and he wished for all the homes to be reconstructed, somewhere across the world the exact number of houses were destroyed and the exact number of people were left homeless.
Jakeem is mentioned briefly by Mr. Terrific while the Black Lantern JSA members attack. Mr. Terrific uses Stargirl, Doctor Fate, and Lightning to make a Black Lantern bomb. He reveals that he can't recreate the power of the emotional spectrum to defeat the Black Lanterns, but he can recreate the energy of Jakeem's thunderbolt. He reveals that when the Black Lantern's attacked, their first target was Jakeem because his thunderbolt could instantly destroy the zombies. The Black Lantern Mr. Terrific (Terry Sloane) himself made sure Jakeem was taken out of the fight. Sloane separated Jakeem from the Thunderbolt and supposedly killed him. Mr. Terrific combines the heroes energy, making a bomb and destroying every Black Lantern in New York.
Jakeem is never seen as a Black Lantern, meaning he could've survived. It's never revealed what happened to the Thunderbolt.
An alternate version of Jakeem appeared as an inhabitant of Earth-16 in The Multiversity: The Just. He instead seems to be in control of the blue Thunderbolt (Lkz) instead the pink Thunderbolt (Yz), summoning him saying "so cool" ("zzzokuuull") instead "say you" or "Cei-U".
Jakeem is the possessor of the Thunderbolt pen, which is the home of a genie. With Thunderbolt as his partner, Jakeem is able to make any number of wishes, which causes much mayhem because of mispronunciations and misunderstandings between the two. There is no limitations to the Thunderbolt's power in this dimension.