Johnny and Plank were in Operation: JUSTICE, where Mandy ordered them to take out Fanboy and Chum Chum, in which they succeeded. They were then ordered to take out Tommy Gilligan, but failed quickly, for Tommy fought back and got Johnny's head stuck in a tree, and Plank was unable to get help.
They made a bigger appearance in Operation: DEATH-EGG, rummaging through Eggman's Scrap Yard for something to get back at the Eds with. After nearly facing the fact that Plank was just a mindless piece of wood, Johnny accidentally tripped and dropped Plank into some spilled intelligence potion from Dr. Eggman, which Plank then absorbed and gained intelligence, motion, and a high British accent. Johnny was immediately surprised at Plank's sudden ability to talk, but Plank simply reminded him of all the other times he talked, and everyone else ignored him (such as Nazz, ignoring him in the Spelling Bee, after he spelled a word with "sheer gusto"). He then concocted a new revenge plan, in which he ordered Johnny to find more hunks of wood and more intelligence potion (or as he called, "that delicious beverage").
Johnny 2x4 then stole part of the wall in Harvey's room in his treehouse, to which he and his friends chased after, eventually following him to their secret underground hideout, where Plank made his new army of Planks of all kinds. After a catchy musical number, Plank caught Sector W and had Johnny knock them out. They were then taken to a dark room, where Plank interrogated and told them of his plan, and Harvey spilling the beans that he's a Kids Next Door operative, and the Supreme Leader's little brother.
In Final Preparations, Johnny and Plank finally led their army to the Brotherhood Base, where Sector W escaped with the help of Charlotte MayHence. They broke into the base, where Johnny and Plank fought Nolan York and Danika. By the time the base exploded, the Plank Army had stolen enough intelligence potion to make an even bigger army.
In Legend of the Eight Firstborn, Johnny and Plank journeyed to the Forest of Light to kidnap the Firstborn, Celebi, in the hopes of using her power to fuel his Plank Army. They successfully kidnapped Celebi from Team Brotherhood and brought them all to his secret lair. Plank used Celebi's power to fuel a mini time machine, using it to send Team Brotherhood and the Toxic Four back to the past. When Cosmo and Nova arrive, Plank uses Celebi to fuel a machine that gives him power over plants. He uses this power to turn Johnny 2x4 into a muscular monster called John Wood. They battle Cosmo and Nova, but they eventually win and rescue Celebi. Later in the story, Plank is planning to ready a counterattack, but his minions decide they aren't cut out for this and go back to doing what they previously did as pieces of wood. Plank admits defeat as Johnny takes him to play with the other cul-de-sac kids.
Johnny ended up in a horrible car crash that ruined his body. They were thankfully found by Team Rocket, who created a cyborg body for the two to use together. They began to work for Team Rocket as John-Plank 20x40.
In Legend of the Seven Lights, John-Plank were ordered by Giovanni to use the R System to transfer Mew's energy into Acnologia's body, which would resurrect him. When Darcy Chariton broke into the Pokémon Palace, John-Plank fought her, but they were defeated as Mew was rescued. Acnologia's body was taken to a different room as Plank resumed work on him, transferring Moon's Tears' energy into his body. In the Side Stories, Acnologia is fully recovered, and John-Plank controls him using microbots implanted in his body. Acnologia guides them to Lunaria, where they find the Tenth Firstborn, Crest in the company of Sector RZ. John-Plank seizes the Firstborn and order Acnologia to attack them.
They have Acnologia take them to the Night Palace, where John-Plank commands him to battle Vaati. Johnny later pulls Plank off of him and attaches Plank to Acnologia's body, allowing him to control the half-dragon directly. Acnologia kills Leanne Grayson, then Diwata attacks him using the power of the Lunar Magic. An enraged Acnologia sets his body aflame and knocks Plank off. Logia morphs into a dragon, and despite Plank's attempts to command him, the dragon burns Plank in Moon Fire.
Johnny created Plank and cares strongly for him. Even with Plank's newfound intelligence, he admits he still needs Johnny's strength. It could be assumed he cares for Johnny just as much.
Harvey snuck into Plank's lair when Johnny stole part of his bedroom wall. Harvey reminds Plank of Eddy.