The original Steeplejack was a man named Jack Mallard who was killed during a fight with Power Man. Another man named Maxwell Plumm would take on the new identity of Steeplejack after breaking into Mallard's apartment and stealing his designs for the acetylene gun and other gadgets. Maxwell Plumm was a building contractor who got into it with Joe Danvers after he was nearly killed while checking out the Monarch Plaza. Joe was saved by Ms. Marvel who was secretly his daughter Carol Danvers. Joe Danvers told Plumm that his building was unsafe and a disaster waiting to happen. Plumm told Danvers to stay out of his business or he would regret it if he was pushed too far. Carol was willing to help her dad as a journalist to exploit Plumm. She discovered that Plumm owed millions to a man named Dominic Varone and was planning to pay him back through the Monarch Plaza project. Plumm was going to use his media contacts and spread a story that Jack Mallard didn't die and that he was after Maxwell Plumm. He would blame the death of Joe Danvers and Ms. Marvel on Mallard and then flee to Brazil with the Monarch profits.
Steeplejack would ambush Joe Danvers and take him back to the Monarch Plaza. He took Danvers to the 40th floor and told him to jump or he would kill him with his acetylene gun. Ms. Marvel intervened just in time and knocked Steeplejack to the ground. Ms. Marvel took her dad to a safer location, knocked him out and hid him underneath a tarp. She would smash through the floor and engage Steeplejack in battle once again. Steeplejack would blast Ms. Marvel onto a freight elevator carrying some boxes of dynamite. He then burned the elevator cables hoping to kill Ms. Marvel in the fall or explosion. Ms. Marvel managed to set the elevator down gently and prevent the explosion. Steeplejack caused some of the structure to collapse which set off the explosives on the bottom floor. Ms. Marvel was able to save her dad and Steeplejack from the collapse. Plumm was apprehended by the authorities and a number of charges were going to be filed against him.
An unnamed Steeplejack and a group of other criminals are later killed by the assassin Scourge at the Bar with No Name.
A third unnamed Steeplejack was seen recently alongside the Ringer and the Tumbler robbing a bank for Roderick Kingsley while the Superior Venom was fighting the Avengers. Unfortunately they were not the only super criminals in the area and the trio encountered Menace and Monster. While his partners ran from the Goblins, Steeplejack held his ground and got off a shot with his acetylene pistol that burnt part of Monster's armor before she slammed him into a chimney with a single punch. As he lay stunned, Goblin Knight found him and despite Steeplejack's pleas to be taken to hospital impaled him with his burning sword.
Steeplejack uses a number of gadgets at his disposal. His main weapon is his acetylene gun that has a number of offensive features. The gun can fire white hot rivets or the setting can be changed to fire a force beam. He also uses a specially designed wire that is pliable like a rope but strong enough to hold tons to tie up his victims. He also wears a thickly padded armor on his costume enabling to blunt punches from Ms. Marvel.