High Jedi General Obi-Wan Kenobi and Marshal Commander Cody were given overreaching command of the units comprising the Third Systems Army, though individual units' day-to-day operations were still commanded by their respective Commanders and Jedi Generals.
The Third Systems Army was the most well-known systems army due to containing numerous elite clone units, such as the 501st Legion, the 212th Attack Battalion and Squad Seven. Units in the Third Systems Army were often deployed in major battles and invasions.
- Battle of Umbara
- Battle of Muunilinst
- Battle of Zaadja
- Battle of Christophsis
- Battle of Juma 9
- Battle of Ryloth
- Second Battle of Geonosis
- Battle of Saleucami
- Battle of Sarrish
- Battle of Skor II
- Battle of Rendili
- Battle of Bomis Koori IV
- Battle of Cato Neimoidia
- Battle of Belderone
- Battle of Nelvaan
- Battle of Coruscant
- Battle of Utapau
- Battle of Jabiim
- Star Wars: Republic: The Battle of Jabiim
- Star Wars: The Clone Wars – "The Hidden Enemy"
- Star Wars: The Clone Wars film / novel
- Star Wars: The Clone Wars – "Innocents of Ryloth"
- Star Wars: The Clone Wars – "Landing at Point Rain"
- Star Wars: The Clone Wars – "Weapons Factory"
- Star Wars: The Clone Wars – "Legacy of Terror"
- Star Wars: The Clone Wars – "The Citadel"
- Star Wars: The Clone Wars – "Counterattack"
- Star Wars: The Clone Wars – "Citadel Rescue"
- Star Wars: The Clone Wars – "Carnage of Krell"
- Star Wars: The Clone Wars: Slaves of the Republic
- Star Wars: The Clone Wars: Republic Heroes
- Star Wars: Clone Wars – "Chapter 22"
- Star Wars: Republic: Dreadnaughts of Rendili
- Republic 67: Forever Young
- Routine Valor
- Labyrinth of Evil (First appearance)
- Star Wars: Episode III Revenge of the Sith