Commander Rick was the commander in chief of the Citadel of Ricks's militia. He was a minor character in the season 3 premiere, The Rickshank Rickdemption, and his current status is unknown but he is presumably dead.
After Rick Sanchez escaped from the Galactic Federation Prison in the body of Rick D-99 in a spaceship, he calls in to the communicators at the Citadel of Ricks. When the Commander tells the station worker to bring Rick D-99/C-137 in, Rick states he will only talk to a Rick with higher clearance. A slightly annoyed Commander in Chief Rick then identifies himself to Rick, which prompts Rick C-137 to swap his mind with the Commander, taking control of his body and identity. Lastly he orders the station worker to blow up the ship with Rick D-99 because "he's a spy" before saying Now I'm gonna go take a shit and leaving.
Rick heads to the station from where the Ricks can teleport the entire Citadel of Ricks to any location in the universe using only buttons and dials. Remarking on how bad of an idea that is, he pushes a worker aside and types in the coordinates to the Galactic Federation Prison and sends the Citadel crashing into it. Again he exits after saying Now I'm gonna go take a shit.
As the possibility that the modified brainalyzer that Rick used to take over other Rick's bodies may have been destroyed exists, Commander in Chief Rick may have been later disguised as Quantum Rick's in order to assassinate the other members of the Council of Ricks.