According to the Territorial Defense Forces of Ukraine, the insignia of the brigade reflected the pride and courage of the defenders of Volyn.

It was mentioned that the red symbolises the bravery, courage and willingness to give one's life for "God and the Motherland", and white represents "purity and integrity".

[13] On 25 April 2024, the insignia of the brigade changed for a final time where the design of the Lubart Castle tower was made to be grey rather than a toned and subdued golden/yellow colour, along with the background colour of the tower being returned to the first design on 30 March 2024, being a subdued green.

In a report by Forbes in late April 2024, it was stated that the brigade is one of the newest and most lightly equipped in the entire Ukrainian Ground Forces.

[21][22] A small amount of M-14 rifles have been seen in use by the brigade with additional attachment such as telescopic sights and bipods mounted.

[30] It was reported by various Ukrainian media outlets that the brigade has fought extensively in the Bakhmut, Kupiansk, and Lyman directions in eastern Ukraine for over a year.

[4] The brigade reportedly fought hard in the direction, allegedly intercepting the Russian 30th Motor Rifle Brigade as well as other units composing the Russian 41st Combined Arms Army when advancing towards the Prohres, a village seven miles to the west along the same railroad linking Avdiivka and Ocheretyne.

In a report by DeepStateMap.Live, an online interactive Ukrainian mapping site, the 100th Mechanized Brigade successfully counterattacked a Russian advances towards Prohres, stopping the assault.

[36] On 18 August 2024, Ukrainian President Volodymyr Zelenskyy recognised the efforts of the 100th Mechanized Brigade in the defense of Toretsk.