The wisecracking loudmouth of the Reds, Grif is somewhat self-centered, acerbic, lazy, and even cowardly. Despised by his teammates Sarge and Simmons, he has the lowest social and, in the beginning of the series, lowest military rank on the Red Team. Simmons and Grif often bicker or chat with each other about the various situations that the Reds encounter. Although Grif's laziness does create problems for the Reds, Sarge always blames him when things go wrong, regardless of Grif's (or anyone else's) actual guilt in the matter. He regards Donut with disdain, thinking him unintelligent, and evidently despises the rookie's general enthusiasm.
Grif has even admitted to being lazy. He has repeatedly admitted to sleeping during staff meetings and neglecting to do his assigned tasks. In one instance when Sarge orders him to run over and find out what Donut was doing Grif responded by saying "Or I could just look through the scope of the sniper rifle, since that's worked the last 800 times."
With respect to personality, Grif is fairly brash and has a flair for melodrama. He is quick to make silly theories or insults, even toward people who could clearly kill him without hesitation. He is also completely averse to fighting, fleeing at the first sign of danger. Physically, a lifetime of smoking and eating bacon flavored marshmallows has left Grif badly out of shape for a soldier in the military, and he is barely able to run 300 feet without running out of breath. After being accidentally run over by Sheila, driven by Tucker, Grif had to have most of his body parts replaced with donor organs left over from Simmons' cyborg operation. Even this event, however, has not compelled him to quit his bad habits.
In Episode 81, Rooster Teeth reveals a new character in , who joins him in the canyon before revealing she is a Blue, and Grif hands her over to the Blues to protect her. Later, when it is revealed that Sarge is still alive, Grif shows his fear of bats when asked to go into the caves to look for him. His fear is largely paranoid, as he becomes jumpy and nervous at numerous moments, even when bats have nothing to do with the situation, such as when he hears some water dripping and he immediately becomes fearful. When attacked by aggressors unidentified by the Reds, Grif refers to them as "bat-people", owing to its inhuman appearance.
When his sister arrived at Blood Gulch in episode 81, she revealed some of his past from before he was drafted; he had taken care of her when their mother had run away to join the circus. When he was shipped away, she then joined the army to be with him again. However, she joined the Blue Army instead, leading to complications with Grif and the Reds upon her arrival in the Gulch.
Grif has undergone little change throughout the seasons. His habits have remained relatively unchanged and his personality remains consistent, a trait noted by the Rooster Teeth crew. Perhaps the largest change Grif had to undergo was after he was run over by in Season Two and Sarge had to implant Simmons's organs in him. After this, he continues to function as per usual.
After the conclusion of the Blood Gulch Chronicles, Grif, like much of the cast, is transferred out of Blood Gulch and sent to another location. At the end of Reconstruction Episode 8, he appears along with Sarge and Simmons. In Chapter 9, which takes place between chapter 4 and Chapter 8, Sarge goes to recruit Simmons and Grif for a mission to stop Washington. It is revealed that Grif was promoted to Staff Sergeant (a fact, as Grif points out, that Sarge is "[not] physically capable" of grasping). Sarge unwittingly saves them from execution by their own team and they travel on the Warthog to the power station to confront the Blues; however, they soon find themselves forced to work with the Blues against the Meta. Later on, Sarge negotiates with Washington for their services and demands Grif be demoted to a rank below private, which Washington grants.
Grif's relationship with Simmons is more complex. Simmons talks down to him and frequently expresses his displeasure of him, while Grif enjoys making Simmons look like a fool and often reminds him that he is pathetically sycophantic to Sarge. Despite their disdain for one another, the pair are often seen together, chatting and bickering. They share a love-hate relationship, with Grif acting the foil to Simmons's straight man.
With the introduction of Grif's sister, Grif displays a protective trait. When she lands in the canyon, he immediately tells her to leave. When this doesn't happen and she is later revealed to be a Blue, he hastily hands her over to the Blues in order to protect her from Sarge and Simmons, a decision he regrets when announces an intention to have sex with her. Later, in , when upon seeing her empty suit of armor, he mistakenly believes her to be dead, he lapses into shock and despair; although this gives way to fury when he learns she is simply naked. This is shown again in when the Reds plan to counter-assault Blue base and Grif notes that nobody else except him hurts Sister, claiming it is his job. In one of the endings of the final episode, Grif kills Tucker for trying to have sex with her, and is then killed by Sister because she was fond of Tucker.
As early as , Grif's desire to quit the army was evident. On that occasion, he expressed his hope that the war was over and he could return home. Since then, he has often complained about being unable to quit, asked outright to simply quit after observing a very bizarre scene, and on one occasion even attempted to get himself court-martialled. His frustration at being in the army is best showcased when, at the end of Season 3 and the start of Season 4, the Red Team emerged back in Blood Gulch, and Grif stood on the clifftop for several hours screaming in despair.
However, in the non-canonical first ending of , after he declares "every man for himself" he actually takes an active part in the fighting; not only does he manage to destroy the Blue's tank, he also kills Tucker, who is about to have sex with Sister. In response, Sister kills him claiming Tucker was nice to her and that she liked him.
In Chapter 9 of Reconstruction, it is revealed that Grif was promoted from private to staff sergeant and commanding officer of a unit of Reds. His incompetence causes his men to mutiny however, and he is set to be executed primarily for selling a portion of the base's ammunition to the enemy.