Proto was an orangutan who lived in Central City in the late 31st century. He was one of the city's council members and a close confidante of Councilor Zaius. Proto was present the day a formal inquest was held against the renegade humans Alan Virdon and Peter Burke. When Virdon stated that humans and apes should live as equals, Proto exclaimed "Sacrilege!" He agreed with fellow councilors Zaius and Grundig that the humans should not be executed, but rather studied to see what made them so different from every other human on the planet.
The only information available about Proto comes from the "Escape from Tomorrow" shooting script. The character is never referenced or addressed by name in the episode, though his name does appear in the closing credits.