Who was the first woman to serve as a U.S. Senator from California?

The first woman to serve as a U.S. Senator from California was Kamala Harris. She was elected in 2016 and took office in January 2017, marking a significant milestone in California's political history. Harris previously served as the Attorney General of California, and her election to the Senate was notable not only because she was the first woman from California to hold that position but also because she was the first African American and South Asian woman to serve in the U.S. Senate overall.

Dianne Feinstein, although a prominent figure and the longest-serving female senator in U.S. history, was not the first female U.S. Senator from California, as she began her Senate career later than Harris. Barbara Boxer also served as U.S. Senator from California but followed Harris, beginning her term in 1993. Alex Padilla is the current Senator who was appointed in 2020 to fill Harris's seat, further preceding his own election. Understanding this context clarifies why Kamala Harris stands as the answer to the question.