In late 1979, Miller left Atari with three other programmers and together they formed Activision. Miller eventually left Activision in 1984 and together with Bob Whitehead formed the game developer and publisher Accolade. Ironically, Accolade hit hard times and in 1999 was purchased by Infogrames which in 2003 changed its name to Atari.
Miller left Accolade circa 1995 and went on to develop handheld devices for golf.