He previously served as the acting fire chief and he oversaw multiple operational and administrative bureaus.

[1] His appointment was made by the Los Angeles County Board of Supervisors, and it followed a prior interim role during Osby's leave of absence in 2021.

[1] On February 28, 2023, the board of supervisors voted unanimously to select Marrone as the department's permanent chief, despite opposition from several organizations.

These groups raised concerns about diversity, transparency, and inclusivity in the department's leadership selection process.

[2] Upon assuming the position, he committed to advancing diversity and equity within the department and stabilizing its budget to enhance service levels.