Major

Depending on the faction, officers holding this rank typically command battalions or act as the executive officer of a larger formation.

In the AFFS a major typically commands a battalion, though elite tank and BattleMech companies were sometimes commanded by a major. Majors use epaulettes with one broad base across the bottom as their symbol of rank.

The FWLM is unique in the Inner Sphere because the militaries of the three largest provinces were integrated into one whole, but each province's military retained their existing rank structure. This meant that officers from the Marik Commonwealth could not have the rank of major, as those units used Force Commander but officers from the Duchies of Andurien and Oriente could hold the rank of major. Regardless of the rank's name, FWLM officers who held it would command battalions, or garrison units that were smaller than regimental size. Prior to the Succession Wars, officers with this rank would command marines aboard DropShips, JumpShips, and WarShips.

In the LCAF the equivalent rank is Kommandant, though the senior battalion commander often carried the rank of Hauptmann-Kommandant.

In the DCMS, a major was formally known as a Sho-sa, while the equivalent naval rank was Dai-i. Both officers wore the katakana symbol for "1" in apple green to show their rank.

Prior to Sun-Tzu Liao's ascension to the Celestial Throne, majors in the CCAF either commanded a 'Mech battalion or a regiment of three air squadrons. Staff officers with this rank often served in diplomatic, and logistic roles for the Senior Colonels that oversaw a Capellan Confederation commonality. The commanding officer of a Capellan Home Guard regiment was typically a major. As part of the Xin Sheng movement, Sun-Tzu Liao implemented a new system of ranks that used traditional Chinese names and brought the CCAF ranks in line with the militaries of other Successor States. Officers holding the rank of major under the older system became Zhong-shaos or Lieutenant Colonels. Sao-shao is the rank used for major after the Xin Sheng movement was implemented.

Due to their unique place in the CCAF, Warrior House company commanders hold the rank of Lien-zhang, which is equivalent to major.