Gruenwald married his first wife Belinda Glass in May 1981. They divorced and later in 1992 he married Catherine Schuller on October 12. They had a daughter named Sarah. Mark Gruenwald died in 1996 from a congenital heart defect at the age of 43.
Mark Gruenwald was a comic book writer, editor and penciler. He began his career in 1976 working for DC Comics on the title Amazing World of DC Comics. He wrote some other stories for DC before he was hired by Marvel Comics in 1978. He spent the rest of his career working for Marvel Comics.
- His last will was that part of him be used in a comic book. His wife, Catherine Schuller make sure that after his remains were cremated, they were mixed with the ink used to print the first printing of the trade paperback compilation of Squadron Supreme.
- No trivia.