When it comes to graffiti history, many of the facts are shrouded in uncertainty, since it is common for graffiti artists to conceal their identity in hopes of dodging fines and jail time.
One fact is certain, though- spray paint itself was invented in 1949 by Ed Seymour in Sycamore, Illinois. Seymour intended on the new creation to be a dispenser for his aluminum paint, but the aerosol paint can ended up becoming the primary tool of a new subculture. (Source)
By the time the 1970s rolled around, spray paint production was in full swing. The big names like Rust-Oleum and Krylon had matured as businesses in the spray paint realm, but they reserved tapping into a market of "protestors and vandals." (Source)
During the 1990s, more and more European companies were manufacturing spray paints with upgraded colors and enhancements. European spray cans remain as the professional-grade items.