Commanders are the second highest rank available onboard Planetary Union vessels. They spend their time on the Bridge seated in equal standing to the ship's Captain advising and informing them on the vessel's necessary objectives. For this reason their authority within the ship is held in high regard by all the crew. Commanders assume the powers and authority of Captain in times they are either incapacitated or otherwise missing in action.
- Strictly speaking, most if not all Union officers of a higher rank seen would have been Commanders. The following are those who are definitively seen as such.
- Ed Mercer commuted to the Epsilon Eridani outpost as a Commander in 2418. In September 2419, he was promoted to Captain and assigned as Commanding Officer of the Exploratory-class USS Orville by Admiral Halsey, thanks to an appeal made by Kelly Grayson.
- Kelly Grayson: The current First Officer of the Orville since September 2419, Commander Grayson requested a transfer to the ship commanded by her ex-husband, Ed Mercer.