On August 10, 2022, Guerrero was nominated to the position of chief justice of California by Governor Gavin Newsom.

[5] Guerrero performed pro bono work as a member of the Immigration Justice Project advisory board.

[5] In February 2022, Guerrero was nominated by Governor Gavin Newsom to replace Associate Justice Mariano-Florentino Cuéllar on the Supreme Court of California.

Guerrero was approved by a 3-0 vote of the Commission on Judicial Appointments on March 22, 2022[6] and is the first Latina to serve on the Supreme Court of California.

[8] As of November 11, 2022[update], following the 2022 election, she was retained by California voters to be elevated as the chief justice with 70% of an affirmative vote.