The following characters are minor characters who have appeared in at least two episodes of the Frontier Fleet: USS Calhoun series. The Calhoun series is notable for integrating junior officers and crewmen as important and influential characters in its stories.
- Azyian, Ensign. This Bolian crewmember is the head of the Operations department during the beta shift. She has appeared as a very minor character in numerous episodes, never leaving the bridge.
- Sheryl Bailey, Lieutenant j.g.. A Human security officer who has been a prominent character in several episodes, as a member of away teams.
- Kodo Baltimore, Lieutenant j.g. A Human security officer who has been a prominent character in several episodes, as a member of away teams.
- Jack Callahan, Lieutenant. Human helmsman, and twin brother of Commander Luke Callahan, he has been a prominent character in numerous stories.
- Jessica Chung, Ensign. The ship's Human transporter chief, she has appeared in several episodes, and has been involved in storylines that take her outside her transporter room.
- Fabio Darelli, Crewman. After first appearing in episode 1x02 ("Maiden Voyage"), helmsman Darelli has been a recurring minor character. He was a prominent character is episode 1x25, "The Explorers' Fifteen".
- Chris Dwyer, Ensign. A recurring, almost always prominent Human security officer, plagued by his past.
- The Emergency Medical Hologram. A mark-IV medical hologram, he has been a minor but recurring character.
- Veeran Hakim, Ensign. Recurring Human science officer.
- Hequill, Ensign. Formerly prominent and recurring character, he was a Cairn science officer.
- Alexia Leal, Lieutenant. Leal, a Trill medical officer, is a recurring and often prominent character.
- Timothy Lynch, Ensign. A mentally unhinged Human security officer obsessed with Counsellor Zela Trunour, he appeared as a prominent character in several episodes before being killed by Ambrose Harris' double from the Parallel Reality in episode 1x12, "Through the Looking Glass". He was most prominent in episode 1x08, "The Search for Dawn".
- Nguyen Dinh Tuan, Ensign. A Human security officer, recurrent in season one, he appeared very little in season two.
- Mahvash Norousyok, Crewman. Captain Jennifer Su's 19 year-old Human yeoman, she is a recurring minor character, notable for her unfailing, bubbly cheerfulness and eagerness to please. She was a prominent character in season one finale "The Mirror Crack'd" (1x26).
- Pak Seung-jo, Crewman. When he first came aboard the ship as an 18 year-old, this Human security crewman was one of the crew's very youngest members. He has been a recurring character, prominently involved in numerous episodes.
- Fabian Perez, Ensign. A Human operations officer, he has been recurring and occasionally prominent.
- Kristjan Roeynig, Lieutenant j.g.. A Human officer who runs the Operations department when no-one else is around to do it, he has been a recurring minor character.
- Eileithyia Sophronia, Ensign. Recurring Human science officer.
- Adlai Stevenson, Lieutenant. This elderly Human engineer was a close friend and assistant to chief engineer Ambrose Harris. Formerly recurring, now retired.
- Chris Su. A Human engineer, she is also the captain's wife, and one of the most prominent 'minor' characters on the Calhoun. She has been a prominent character in numerous episodes.
- T'Salia, Ensign. Recurring Vulcan engineering officer.
- Steven Trunour, Ensign. A recurring Human security officer who has been a prominent character in many episodes.
- Zela Trunour, Lieutenant junior grade. Steven's Orion wife is a counsellor, and one of the Calhoun’s long-standing recurring minor characters. She has been a prominent character in many episodes, and is noted for her gentleness and belief that anyone can be redeemed. She was a central character in episode 1x08, "The Search for Dawn".
Civilians aboard the Calhoun or Delta One
- Stan & Dan. Half-brothers who own a bar on Delta One and are suspected of being involved in illicit activities, they have appeared as minor characters in numerous episodes.
- Q'Orianka. Formerly recurring Human civilian aboard the Calhoun, she was a rescued slave originally from a colony of Humans who had settled in the Delta Quadrant after having accidentally traveled through time.
- Qar. A recurring, frequently prominent Ocampa character, he is a former Borg drone, and the husband of Commander Dawn Summers.
- Maje Jarit. The leader of the small Kazon Xongar sect, he has more often been an antagonist than an ally to the Calhoun’s crew. He once kidnapped two crewmembers, but relations between the ship's crew and the Xongar were later normalised. Jarit was a prominent character in the story arc composed of episodes "Diplomatic Roundup" (1x07), "The Search for Dawn" (1x08) and "Summer Darkness" (1x09).
- Krog. A Klingon captain and friend of Commander Dawn Summers', he has been prominent during his rare appearances.
- List of minor Calhoun crewmembers on the Frontier Fleet website