According to Bob Geldof, he wrote the song after reading a telex report at Georgia State University's campus radio station, WRAS, on the shooting spree of 16-year-old Brenda Ann Spencer, who fired at children in a school playground at Grover Cleveland Elementary School in San Diego, California, on 29 January 1979, killing two adults and injuring eight children and one police officer.
Spencer showed no remorse for her crime; her explanation for her actions was "I don't like Mondays. This livens up the day".
Geldof had been contacted by Steve Jobs to play a gig for Apple, inspiring the opening line about a "silicon chip".
The song was first performed less than a month later.
Geldof explained how he wrote the song:
Geldof had originally intended the song as a B-side, but changed his mind after the song was successful with audiences on the Rats' US tour. Spencer's family tried to prevent the single from being released in the United States, but were unsuccessful.
In later years, Geldof admitted that he regretted writing the song because he "made Brenda Spencer famous".