On November 29, 2021, California Governor Gavin Newsom appointed Chau to be a judge in the Los Angeles County Superior Court.

[5] Chau also served as a member of the following standing committees: Appropriations, Judiciary, Jobs, Economic Development and the Economy, Natural Resources, and Privacy and Consumer Protection.

He was also a member of the following Select Committees: Asia/California Trade and Investment Promotion, California's Clean Energy Economy, Cybersecurity, and Regional Transportation Solutions.

Other laws passed by Chau include prohibiting the sale, purchase and use of hacked data;[8] making it a crime to assist in soliciting another to commit hacking;[9] requiring credit reporting agencies to fix vulnerabilities regarding data breaches;[10] protecting individuals' privacy from devices like drones;[11][12] authorizing the California Military Department to conduct cybersecurity assessments in schools;[13][14] requiring disclosure of a data breach to California residents when the encryption key is lost;[15] and authorizing local governments to provide broadband services, while adhering to “net neutrality rules”.

Moreover, Chau passed laws to help curb climate change;[21][22] protect water resources through groundwater cleanup funding;[23] combat wild fires through forest management;[24] protect seniors against elder abuse;[25] require Emergency Medical Technicians (EMTs) to receive training on how to interact with dementia patients and their caregivers;[26] mandate advance notice before increasing life insurance costs on consumers;[27] ensure that students in California receive instruction on the Chinese Exclusion Act of 1882 and the contributions made by Chinese Americans in establishing the Transcontinental Railroad;[28] protect students by removing from classrooms teachers charged with a sex offense;[29] safeguard children from cyber sexual bullying;[30] prohibit the online marketing of cannabis products or services to minors;[31] and legally protect Good Samaritans that break into hot vehicles to rescue children.