The leadership positions:
Squad Leader (SL)
Rank(s): Sergeant, Staff Sergeant
The Squad Leader supervises his squad in and out of combat and is responsible for making sure his entire squad is trained to standard. The Squad Leader has the right to select an Assistant Squad Leader (ASL) who is a Corporal. The ASL leads the second team (the Bravo Element) if the Squad has to split up for a mission.
Platoon Sergeant (Plt Sgt.)
Rank(s): Staff Sergeant, Gunnery Sergeant
The Platoon Sgt. is the senior-most enlisted soldier in the platoon. The Plt Sgt. is the principle assistant/advisor to the Platoon Leader and assists with running the Platoon. The Plt Sgt. assists with the training of squad leaders, but is primarily concerned with overseeing the squad members. In lieu of a Lieutenant, the Plt Sgt. can become Platoon Leader.
Platoon Leader (Plt Ldr)
Rank: 2nd Lieutenant
The Plt Ldr. is the highest level of authority within the platoon. The Plt Ldr generally has the most combat experience in the platoon as well as the most experience with his profession/class and uses that for training. A requirement for Plt Ldr being commissioned as a 2nd Lieutenant is general expertise in his profession. As a commissioned officer, the Plt Ldr. is the link between the Command Staff and the platoon.
Company First Sergeant (Co 1stSgt.)
Rank: First Sergeant
The Co 1stSgt. is the senior enlisted Soldier in the Company. He keeps the Company Commander up-to-date on any issues on all levels in the Company, especially with the enlisted Soldiers. The Co 1stSgt also trains the NCO's and supervises the SNCO's.
Company Executive Officer (Co X.O.)
Rank: 1st Lieutenant
The Co X.O. is the Second-in-Command of the Company. The Co X.O. has a great deal of leadership and combat experience and is usually the senior Platoon Leader.
Company Commander (Co C.O.)
Rank(s): Captain, Major
The Co C.O. is the Commanding Officer of the Company. The Company Commander coordinates with the Battalion Commander about the mission of his company in large operations. A Company is typically charged with a major objective in a large operation. The Co C.O. typically has the most combat experience and uses that to train his company. A Company Commander is a general expert in his profession and trains all Soldiers of the same profession.