The cub, which has not been given an official name yet, was born at the zoo Sunday to the 9-year-old Sumatran tiger Leanne, the San Francisco Chronicle reported.
Zookeepers said they won't know the cub's sex for at least two more weeks.
"We really prefer to allow mom and cub to have a really solid two-week bonding time" before we get involved, said Corinne MacDonald, curator of carnivores and primates at the zoo. "It wiggles a lot and squirms a lot. The active part is what we really look for right now."
MacDonald said Leanne is doing a great job so far with her newborn.
"Mom is really attentive; she's grooming, she's paying attention to the infant," MacDonald said. "The infant makes sounds, it coos. It'll scream and screech and cry when it gets real hungry. We can really see [Leanne] choosing to get up only when the infant is really sound asleep, so she's a great mother."
Leanne's cub is the first tiger to be born at the San Francisco Zoo since 2008. Before that, the last litter of tigers was born in 1976.
"We are thrilled with this birth," said Tanya Peterson, head of the zoo. "Sumatran tigers are a critically endangered species ... which makes every birth so impactful for these beautiful animals."