Matt Hullum states that he initially modelled Sarge's voice on that of R. Lee Ermey, the actor who portrayed Hartman, but by Season Four the character's voice became more gruff and less nasal. The change in the voice is such that Hullum notes people will often ask who voice-acted Sarge in the initial episodes, believing that Hullum himself did not.
Introduced in the first two episodes, Sarge's disposition is quickly established, particularly his relationship with and , in a conversation that the writers modelled on one that they themselves had over the resemblance of the Warthog to a Puma. When the Blue Team launched an attack sometime after, Sarge was possessed by the dead Blue team leader, and shot in the head by the Blue rookie, . Thanks to Grif, with the use of CPR, he survives.
In season 2, Sarge is forced to build two new, permanent robot bodies for the Blues, and implants a microphone in one and a bomb in the other. This leads to both teams being blasted into the distant future during season 3. Once there, Sarge leads both teams in an assault on a fortress occupied by , the common enemy of both teams. During a battle against O'Malley and a robot army, Sarge and the Red Team leave the Blues to battle alone, in order to go in search of the source of a distress signal and end up returning to Blood Gulch.
In season 4 Sarge, and the rest of the Reds, return to Red Base. The team then finds , a robot built by Sarge who had defected to the Blues and then been captured by O'Malley. From late in , Sarge had been attempting to retrieve the orders from Red Command that are stored in Lopez's head. Due the fact that Lopez only speaks Spanish, and had translated the message into Spanish, Sarge kidnaps , the Blue Team's talking bomb to translate the orders, which turn out to be useless. The Reds are then attacked by the Blues, and Sarge radios command reinforcements. When a ship arrives, the pilot informs them that she was sent to replace a dead commanding officer. Sarge at first insists that he is alive, but Grif brings up the possibility of Red command being wrong about other stuff such as the idea that the Blues "don't suck". Sarge, not willing to accept such a thing, believes then that he is in fact dead, and the other Reds bury him.
By , he has disappeared from his grave, having fallen into the underground cavern. In , Sarge believes that he is in hell since he's underground. He confirms this when Donut arrives. He soon gets contact from Simmons and Grif, who are in the cavern to rescue them. Upon discovering there are other people in the cave, he decides they must find them, but the team gets sidetracked upon finding some surveillance equipment showing the Blues invading their base. Sarge organizes a plan to capture the Blue Base in retaliation, and attempts to call Vic Jr for reinforcements; however, the latter promptly cuts him off. Shortly after, the Reds capture the empty Blue Base and watch the Blues being attacked by multiple ; unwilling to let someone else take the glory for defeating the Blues, Sarge leads the team against the Wyomings. O'Malley starts jumping from person to person and Church asks Sarge to disable the ship so that O'Malley can't escape in it. Sarge, however, decides to blow it up instead, and puts Andy on the ship. When O'Malley finally jumps back into Tex, they take off in the ship. Sarge orders Andy to blow up the ship, to the horror of Church. In the official ending to the series, when Simmons asked if they would continue fighting the Blues, Sarge replied with, "No, Simmons. I think they've had their asses kicked enough for one day. Let's leave some for tomorrow." Shortly after, he builds a new ATV out of spare Warthog parts and asks Simmons and Grif to name it.
Reconstruction, which is set some time after the events of the Blood Gulch Chronicles, shows Sarge and Lopez as the only remaining Red soldiers in the canyon, the others having been transferred. Sarge refuses to relocate until the battle is over by his standards, which means no Blues remaining, but the only Blue, , is female, which disallows Sarge from attacking her, making them, as he describes it, "locked in an epic stalemate." Because of his refusal to leave, he is technically AWOL. To be some help, he told where Caboose has been relocated. He is later tricked by to reassemble his team and engage Washington, Caboose and Church. Afterwards, the Meta returns to where the Reds and Washington's team are and attacks them before leaving. Much later, he and the Red Team managed to secure another Warthog (albeit a rickety one) and spearheaded the assault on Outpost-17B "Valhalla". After infiltrating Command, Sarge asks Simmons to attempt to wipe all trace of every Blue from the database.
Sarge has little to no respect for Donut, calling him "a worthless turd" (which Donut mistook for a review session) and often calls him rude names referring to his pink armor, such as "Strawberry Shortcake" or "Princess Peach". When Donut was crushed by the ship, Sarge described Donut as "someone I knew, but I don't really want to reflect on how deep our relationship went." There are times when Sarge appears to value him, such as when Sarge promoted him to be his second-in-command after exiling Simmons, and when Donut stole O'Malley's hovercraft in Episode 57 and ran over a robot soldier "and a few other innocent pedestrians," Sarge responded with: "I'm so proud of you!"
Lopez is shown to dislike Sarge, calling him a stupid old man, and seems delighted when Sarge leaves Blood Gulch. When Sarge makes his goodbyes, Lopez tells him "less talking, more leaving" (which Sarge can't understand due to his poor knowledge of Spanish).
Simmons is the one that Sarge values the most, but they also have a strained relationship. Simmons is well-known for his sycophantic attitude towards Sarge, who turns against Simmons whenever he disagrees with him. In Season 4, when Simmons noticed Sheila was roaming the canyon, Sarge believed he was delusional and cast him out from the Red Team. Later on, when Simmons returns, Sarge's attitude remains the same, calling him a traitor on occasion.
Sarge has criticized Grif and praised Simmons for the same action. When Grif saves Sarge's life by performing cardiopulmonary resuscitation (CPR) after being shot in the head by Caboose in season 1, Sarge initially thanks Simmons. However, upon learning who had actually resuscitated him, Sarge proceeds to berate Grif at length for the illogicality of using CPR "for a bullet wound in the head". Rooster Teeth had initially considered making the former event a turning point in Sarge's relationship with Grif, but decided in the end that friendship would be too far-fetched.
In Season Five, a complete dependence on command was showcased; when a new arrival in the canyon, who the Reds think has joined their team, informs them that command sent her to replace a dead commanding officer, Sarge at first refuses to believe it, but when Grif makes a few clever comments about how command could be wrong about other things which Sarge staunchly believes in, he believes that he is dead and the Reds give him a funeral.
Sarge also appears to act as the Red Team's medical officer, as he has performed surgery on both Simmons and Grif in a relatively short amount of time, and both seem to be healthy. However, Sarge clearly knows very little about bodily functions, as he uses a diagram of a cow as an aid during Grif's surgery, claims that the body can produce any oxygen it needs when under stress, advises Caboose to lift a heavy weight with his back as opposed to his legs and claims that the chest is "strictly for digestion".