[15] The following year, in 2018, Brawner took command of the 103rd Infantry Brigade under the 1st Infantry Division, and was tasked to root out the remnants of the Islamic State-associated militant terrorist organization Maute Group and its allies within Western Mindanao, including the death of Owayda Marohombsar, also known as Abu Dar, and was the successor of Isnilon Hapilon as the head of the Islamic State-linked terrorists, and the last remaining leader who escaped the Battle of Marawi and was neutralized after follow-up operations.

[4] In the aftermath of the Death of Darwin Dormitorio due to hazing, Brawner was named the acting-Commandant of Cadets of the Philippine Military Academy in 2019, along with Rear Admiral Allan Ferdinand Cusi as its superintendent officer-in-charge, following the resignation of their predecessors, then-Brigadier General Bartolome Vicente Bacarro as Commandant of Cadets, and Lieutenant General Ronnie Evangelista as PMA Superintendent due to command responsibility.

[9] On July 1, 2021, Brawner was named commander of the 4th Infantry Division, in charge with counterinsurgency operations in Northern Mindanao and Caraga regions.

[13][12] During his term as the CGPA, Brawner initiated reforms under his leadership thrust, known as "SERVE" thrust, which stands for Soldier, Enhance, Resources, Victorious and Elections, and is aimed at strengthening the soldier's well-being and mental health, enhancement and modernization, resource management, attaining victory against the CPP-NPA-NDF, and securing the country amidst the 2022 Philippine general elections.

Brawner also launched initiatives aimed at enhancing the personnel's mental health, and expanded benefits of Citizen Armed Force Geographical Units (CAFGU).

UNITY stand for Unification, Normalization, Internal Security Operations, Territorial Defense, and Youth, which is aimed at strengthening a unified organization, the normalization process of the Bangsamoro Region, intensified operations against insurgency and terrorism, preparedness against external threats, and youth development, including the potential revival of the Reserve Officers' Training Corps.

[27] In September 2024, Brawner expressed his desire to continually sustain the deployment of the US-made Typhon missile launcher in the country, citing the system's capabilities for external defense operations.

He emphasized the military’s commitment to their well-being, stating, “We are here to support them every step of the way.” The event was part of pre-anniversary activities for the AFP's 89th anniversary, highlighting its dedication to the welfare of its personnel.