Peter Cooper married Sarah Bedell, who proved to be a supportive and devoted partner throughout his life. Their relationship was characterized by mutual respect and shared values.

Peter and Sarah had one child together. Edward, like his father, became a prominent industrialist, politician, and philanthropist.

Cooper placed great emphasis on family values and maintained close relationships with his wife, son, and grandchildren. He instilled in them a sense of social responsibility and a commitment to giving back to the community.

Peter Cooper died in New York City at the age of 92. He was widely mourned as a visionary industrialist, a generous philanthropist, and a champion of social justice.