The vaudevillian-style song is about medical student Maxwell Edison, who uses his silver hammer to murder his girlfriend, then his teacher, and finally a judge. According to McCartney, it epitomizes the downfalls of life. He said in 1994:
"Maxwell's Silver Hammer" is my analogy for when something goes wrong out of the blue, as it so often does, as I was beginning to find out at that time in my life. I wanted something symbolic of that, so to me it was some fictitious character called Maxwell with a silver hammer. I don't know why it was silver, it just sounded better than Maxwell's hammer. It was needed for scanning. We still use that expression now when something unexpected happens.