Creation

Harvey Musgrove was created by Mark Schultz in a story he wrote for Superman: The Man of Steel #91. 

Major Story Arc  

Nemesis

Harvey Musgrove was a board game developer for Wackyland Games who had an idea of his stolen by a co-worker. Soon after this, Harvey began noticed Superman frequently flying by his apartment window while he was working on his next game idea (unbeknownst to Harvey, Superman was simply investigating the area due to a series of arsons). Harvey didn't think much of it until his co-worker began snooping for clues to Harvey's next idea , and remarked that whatever his next idea would be, he was sure it'd be super.  
This led Harvey to believe that Superman had been working with his co-worker against him and that he'd been spying on him all along. Harvey quickly began taking countermeasures by putting the plans for his game in lead-lined boxes and lining a hat with aluminum foil just in case Superman secretly had mind-reading abilities. 
Harvey surmised that because his latest board game idea was about saving Earth from an alien invasion, Superman felt threatened by it, since it could provide people with ideas on how to prevent an actual invasion by aliens like Superman. After various setbacks in getting his game produced, Harvey finally lost it when he found Superman putting out a fire in his apartment that he believed he'd started in order to destroy his work (this fire was in actuality the work of the arsonist Superman had been looking for). Harvey punched Superman, only to give himself a broken hand, and when paramedics tried to treat him, he thought they were trying to inject him with a memory-erasing agent. Harvey was eventually sent to a court-ordered psychiatrist, Dr. Samenpur, who he calmly tried to explain his story to.  
However, when Harvey realized that her name was actually an anagram for 'Superman,' he concluded that she was working with him and shoved her out the window, only for her to be saved by Superman. Harvey once again accosted Superman, telling him he would never let him win and that they only way he could stop him was to kill him. Harvey ended up being apprehended by the police for his attempted murder and was sent to the Metropolis' low-security Mount Hope Home.