Marcel can be described as being the life of the party. When he was introduced, Marcel was shown to apparently be diabolical and dangerous as well as wicked but has since proven himself to be even more moral than Klaus. Marcel is very charismatic and uses said charisma as much as his vampire powers to get what he wants from others. Marcel enjoys his vampiric life and likes living in the French Quarter, considering it to be a home to keep and fight for. He is also very brave, being one of the very few who can speak defiantly in Klaus' presence without worrying about his own life in the process.

He takes his role as leader seriously and enforces the rules he made without fail, though he is not above getting carried away since he supposedly killed a witch in front of many viewers for this reason, though its revealed that said witch used magic and took part in the harvest ritual where she had her own daughter sent to her death. He also seems to genuinely care for his subordinates, having stayed at the side of one dying from Klaus' werewolf bite until the latter provided him with the cure. Marcel also seems to be understanding as shown in his quickness to forgive Klaus for biting his friend when Klaus gave him the cure and asked for forgiveness. He is also shown to be, unlike many people in positions of power and privilege, reasonable and approachable, willing to do favors for people. While not arrogant, he has displayed over-confidence when confronted by beings more powerful than him, such as when he spoke down to Klaus, disregarding that he would be nothing if it wasn't for Klaus, the Original Hybrid, much more powerful than any non-original vampire in his "army", though while Klaus did make him who he was, he also wasn't always benevolent, as he daggered Rebekah for getting too close to Marcel, this affected Marcel deeply and it caused him to resent Klaus as well as eventually turn against him.

Marcel is ruthless, but not completely without mercy; best demonstrated by the fact that he prefers to kill his victims by snapping necks, as opposed to other Vampires, who use more inhumane methods like heart extraction, decapitation, and staking. In fact, Marcel has so far been seen to actually permanently kill someone only five times: One was with Jane-Anne, and the other was with Bastianna. The latter via decapitation, as he needed her death to resurrect Davina. The last witch he killed was Monique, as Marcel had to kill her in order to save Klaus' newborn child. The other two were Tina, Josh's former friend and a werewolf who bit Gia.

He likes to have fun and enjoys being a vampire. He takes pride in who he is. Also, he's intelligent, being able to run a city and maintain it, being much better at it than Klaus, as the latter's leadership was not popular or respected by any faction. He’s very competitive too. Like Klaus, Marcel likes to think up contingencies; he requested Davina to figure out the fatal weakness of the Original Vampires, not aware that the death of an Original Vampire would also mean the deaths of all other vampires sired from their bloodline, including himself. Indeed, one of his weaknesses is that being a recently-introduced character, Marcel knows little about the nature of the Original Vampires, such as Klaus' blood acting as a cure for a werewolf bite and that if one Original Vampire dies, all of their bloodline die too in matter of hours, however, not even the Originals themselves knew of the bloodline problem as it was only revealed with the death of Finn. As with Klaus, Marcel also has very little tolerance for disloyalty, having killed a transitioning vampire purely because she opted to save herself over her companion as well as verbally berate him.

In Sinners and Saints, it was revealed that Marcel's cruelty was only to protect Davina, who was supposed to be used in a blood sacrifice so the witches in the French Quarter could keep their powers. It was also shown that Marcel planned to raid the ritual with the full intent of saving the four witches that were to be sacrificed, including Davina, but arrived too late and only managed to save Davina. Marcel's reasons for killing witches who practice magic was to keep them from killing Davina, as he himself had known what it felt like to be treated as a tool and not a human being. It was because of this that Marcel created a rule against people abusing children in the Quarters. Marcel's reason for hiding Davina was also revealed; to stall the witches until The Harvest was passed and the witches would lose their powers, enabling Davina to live a normal life as she always wanted ever since the Harvest. When Tyler told him of the existence of Klaus' unborn child, along with the potential danger it may pose to the vampire race, Marcel was visibly conflicted on what he should do next but chose not to harm the baby, possibly due to the fact that he doesn't hurt children, or possibly he did not want to risk Klaus' wrath on him, as he knows that Klaus cares about his family, and he will kill anyone who tries to hurt or kill a member of his family.

While Marcel can be seen as a hypocrite for claiming that he dislikes people who have betrayed their friends, when he himself has betrayed Klaus, he has never betrayed anyone unless they have plotted or done damage to him first as Klaus daggered Rebekah simply for loving him and kept them apart for 52 years, This caused Marcel to plot ways to be with Rebekah, even if it meant finding ways to get rid of Klaus, whom Marcel would likely no longer consider a friend after what he did to Rebekah.

Because of his protectiveness towards Davina, Marcel doesn't hesitate to kill any witch that practices magic in the French Quarter to keep them from finding her. However, he is more merciful towards anyone who breaks his other laws, as shown by the countless vampires he kept locked in the Garden instead of killing them, which would take much less effort to do. He went out of his way to save the nightwalkers on his territory when the Faction incited an attack on them, and has yet to be seen dealing with other vampires in ways other than snapping their necks, implying that he really does care for his own kind.