The past history and origins of the Magician are unknown. He established a reputation as a talented magician for large parties and other functions
In his first appearance, he convinced the wealthy Sterling Stuyvescent to hire him to perform at his party. After performing a few tricks, he made a large canvas appear and drop on the party-goers. While they struggled to escape, he relieved them of their wallets, purses, and jewels. The Wasp was present at the party and confronted him, but he sucked her inside his magic wand and vanished in a puff of smoke. Giant-Man's trusty ant brigade warned him about the Magician and the party, and he used a flying ant-driven sleigh to go there, but he was too late.
Unable to locate the Magician, Henry Pym made a public announcement about a large party on the luxury yacht "Neptune" in order to draw him out. The Magician showed up as expected, but there was no party, merely a trap set by Giant-Man. The Magician blinded Giant-Man with a large cloth and escaped back up into his blimp. Giant-Man recovered , lassoed the blimp, climbed the rope at ant size, and freed the Wasp. The Magician saw him and sent his attack rabbit after them. Giant-Man shot up to king-size after the Magician, who managed to hypnotize him. The Wasp saved the day by opening the air release valve from the blimp, causing it do drop slowly into the river, shocking Giant-Man out of his trance. The police were waiting to snag the water-logged Magician. If only they were giant-sized, he could have hypnotized them, too!
In his second appearance, the Magician escaped from prison. While Giant-Man was out looking for him, the Wasp went to a fashion-show, which featured outfits patterned after her many costumes. The Magician figured she would not be able to resist the temptation to see the show. He appeared at the show, used his wand to lock the doors, and then sent it to pinpoint the Wasp, which it did, just like a divining rod. She shrank down, but he put on his "Opto-Ray Magnifying Glasses" which allowed him to track her even at wasp-size. He sprayed a heavy dust to weigh down her wings, but she managed to glide onto the escalator. When he came after her, she jammed his cane into the moving stairs, and then sent a toy robot to tie him up; that held him until the cops came to take him away.
The Magician used unknown means to perform acts of "stage magic". He could actually pull trained rabbits from his hat, which were more than willing to attack ant-sized people. He could appear and disappear at will, usually covered by a burst of smoke. He usually did this by quickly climbing or dropping down from a nearby rope attached to his own personal dirigible. He could levitate rope on which to climb to make an escape. He could seemingly produce doves, roses, a large tarpaulin to drop on others, etc. He'd pull coins out of other people's ears. Some of his feats were accomplished via his magic wand, which had a suction motor able to pull small objects into it, fire them out of it, or manipulate small objects from a short distance. He often used "magic words" in conjunction with his "powers" such as "Abra Kadabra! Alla Kazam".
He apparently had real powers of hypnotism. Of course, anyone with very big eyes would be hypnotized all the more quickly.