Stargate SG-1 is a standout among science-fiction TV series, and not only because of its thought-provoking stories and charismatic cast. The show also features a wealth of memorable guest stars, characters that might show up for one episode or multiple, with arcs that span entire seasons. Many of these characters have gone on to earn their place in Stargate history, and some even end up in spinoff show. A few are beloved among fans simply due to their longevity on the series, or just because they make a really entertaining villain. In such cases, the stories of background characters can often become just as engaging as those of the main SG-1 team.

The show focuses on the many planets incorporated into the Stargate network, and the people SG-1 encounters throughout their travels. Aliens, gods, rebels and more become acquainted with SG-1, but there are a select few that have lasted several years on the show. The best recurring characters are the ones who prove themselves to be a match for SG-1, either as an ally or an enemy. Having a decent sense of humor helps, too, particularly around Jack O’Neill.

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Thor

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Long before Chris Hemsworth adopted the name of the Norse god, Stargate SG-1 established Thor as one of SG-1’s oldest and most loyal friends. Thor is a member of the Asgard, an ancient race of aliens who have acted as peaceful benefactors to humanity for generations. Their advanced technology allowed them to form the Protected Planets Treaty, preventing the Goa’uld from plundering human-settled planets for hosts.

Needless to say, the Asgard are considered the best allies of Earth, and Thor himself has a personal relationship with SG-1. Most notably, Thor and Jack helped to broker the aforementioned treaty with three System Lords, and the Asgard and Stargate Command helped one another fight the Replicators. While watching Stargate SG-1, seeing Thor is always a relief. No matter the crisis, Thor will provide help, answers, or a witty comeback.

Catherine Langford

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Few characters are as important in the Stargate canon as Catherine Langford, who appears in the original Stargate movie, as well as Stargate SG-1 and Stargate Origins. Langford is the daughter of the archeologist who discovered the first Earth Stargate, which was buried by the Ancient Egyptians. Her background and interest in her father’s discovery – which she witnessed – led her to participate in the then unnamed Stargate project. She later recruited Daniel Jackson, an Egyptologist and linguist, who played a crucial role in opening the Stargate and destroying Ra.

Catherine shows up repeatedly in early Stargate SG-1 episodes, as she is a mentor for Daniel and knows the most about the Earth history of the Stargate. Catherine, more than most characters, struggles with the consequences of reintroducing the Stargate. Her character adds pathos to every episode that features her.

Ba’al

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Every story needs a villain that the audience loves to hate, and Ba’al, who has the honor of being the very last System Lord, fills that niche in Stargate SG-1. Ba’al was an underling of the Goa’uld Ra before his death, but once he was gone, Ba’al wasted no time in claiming Ra’s territory for his own. He went on to accumulate massive amounts of power, repeating the process when the demonic Goa’uld Anubis was dethroned millennia later.

As a god-king, he spent most of his time brainwashing Jaffa, plotting mass-murder, creating clones of himself, and time-traveling, making him one of the worst pests of the galaxy. He was also the personal nemesis of SG-1, who have both fought him and been forced to work with him during the TV series and its sequel movies. Basically, he has the pantomime effect of making the audience boo when he comes on-screen, making him the best sort of bad guy.

Bra’tac

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Like Teal’c, Bra’tac is a Jaffa, a member of the race bred to be hosts to the Goa’uld and their offspring. Bra’tac was a father figure to Teal’c in his youth, and taught him to doubt the Goa’uld, who installed themselves as deities to be worshiped by all Jaffa people. Bra’tac’s instruction proved instrumental in the fall of the Goa’uld, as Teal’c went on to join the Stargate program, allying their people with Earth.

Bra’tac also worked to build up a resistance movement among the Jaffa, seeking his people’s freedom. His efforts resulted in the birth of a new Jaffa civilization, one unburdened by oppressors. Bra’tac is cast in a fatherly role when it comes to SG-1, particularly with Teal’c. He takes care of Teal’c’s family, and acts as his confidant when things are dire. His considerable age also ensures he has very little social decorum, which makes him great fun in among stuffy Air Force personnel.

Walter Harriman

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The character of Walter began as little more than a part of the background, hiding in plain sight as the nameless operator of the Stargate dialing system. His character indicated when the chevrons on the gate were encoded, and his most frequent line was the signal that the plot was underway: “Unscheduled off-world activation.” Yet, the strong performance of the actor and the consistency of his presence enamored fans, earning him a firm place in the canon of Stargate SG-1.

In season 4, Walter was named directly in an ad-lib by Richard Dean Anderson, who played Jack O’Neill; from there the character’s role grew even further. He provided support to General Hammond, and often aided Captain Carter in her research. In the end, Harriman became one of only seven characters to appear in all ten seasons of Stargate SG-1. Not bad for a guy who didn’t have a real name for four years.

Many side characters of Stargate SG-1 developed into irreplaceable parts of the overall story, some taking multiple seasons to do so. Honorable mentions to the list above are Martouf (a Tok’ra soldier), Sha’re (victim of the Goa’uld, and Daniel’s wife), Cassandra (Dr. Frasier’s prophetic daughter), Martin Lloyd (an alien immigrant on Earth), and Richard Woolsey (an internal SGC investigator). Whether an ally or an enemy, the best chance a character on this show has at returning is to be memorable – and to put SG-1 through their paces.

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