Fernandez worked on the Cream Soda Computer with Steve Wozniak in 1971, the first computer designed by Wozniak and built using spare parts from Wozniak's job. He would later join Apple and work on both the Apple I and Apple II personal computers, and in the 1980s was a member of the Apple Macintosh development team. He contributed to several user interface aspects of the classic Mac OS, QuickTime and HyperCard and owns a user interface patent granted in 1994. He was laid off from Apple in 1993