A former clergyman now lost to debauchery, Swanson has fallen a long way from the standards he once set himself and struggles with many demons. If he hadn’t saved Dutch’s life in the past, it’s unlikely the gang would have kept him around for this long.
—Description by Rockstar Games.
Swanson worked as a clergyman in the past, but as he indulged in earthly pleasures such as alcohol and sex, he slowly lost his job and his family, as well as his faith. At some point, he affiliated himself with a woman named Margaret, but he never goes into detail about his relationship with her. Under unknown circumstances, Swanson saved the life of Dutch van der Linde at some point; with Dutch in his debt, Swanson was allowed to stay with and join the Van der Linde gang.
Arthur has to go find Swanson, who was last seen near a railroad station. After going to the station, he finds Swanson very drunk and playing poker with two men. Swanson then tells him that Arthur has freed him, and runs away, forcing Arthur to go in pursuit of him. Arthur finds him being beaten up by a buff man, who Arthur can either kill or knock unconscious. While Arthur was busy fighting the man, Reverend once again escaped and got himself stuck on the top of the railroad tracks. Arthur will go and pull him out right before the train goes by, and bring him back to camp.
During a discussion with Hosea at the campfire, Swanson reveals that he was once married, but unbeknownst to him, the woman was already married, meaning they were committing bigamy. He states the law caught up with them in San Francisco, but she escaped onboard a ship to Shanghai.
After Arthur returns from Guarma Swanson has cleaned up his act and is now sober and functioning well. He eventually chooses to leave the gang, due to the gang's collapse. If Arthur hasn't helped Sister Calderón earlier, Arthur meets him one last time at Emerald Station after the mission The Fine Art of Conversation, in which Swanson gives wise words about Redemption and Honor to his dying friend. The dialogue in this encounter depends on the player's honor.
Swanson is a broken and disheveled priest, often drunk. He is also a secretive drug addict, as Arthur can find the Reverend’s bible hiding a syringe, a tourniquet, and a bottle of morphine. Later in the story, he eventually sobers up and becomes more responsible and mature.
Swanson has red hair with grey patches, indicating his aging. He has a large, curly mustache, and wears standard black priest attire. During chapters 3-6, he can often be seen without his hat and robe.
“Love yourself a fire.” It's one of the blessings; freely given to all. And yet, perhaps, not freely given. I am reminded of Prometheus. In many ways, Greek myths are best in explaining the very punishment that imbue our daily existence with their piquant tortures. Sure, we can have fire. And we can have the knowledge of fire. But with that comes the knowledge of everything… We become like a god, because to be all powerful is to be all suffering. Yes… thus, Prometheus gave us light, and warmth, and eternal damnation, and the awareness of our isolation for everything holy. Quite the conundrum, fire. It’s enough to make a man drink… or worse.
—Swanson during a camp speech around the bonfire.
It appears to like this place, and wants to stay.
—Swanson to Arthur, when asked why his foot got caught in a railroad track.
You know... it's not too late to repent, my Mexican friend.
—Swanson to Javier in the middle of his morning prayer.
Swanson has the very first line of dialogue in Red Dead Redemption 2.
Swanson is shown to be Protestant. In one camp interaction in Colter, he is seen reading Isaiah 40:20-31 from the King James Bible, though he isn't sure what the verses meant to him. In another camp interaction, he is seen approaching the genuflecting Javier and telling him to repent. Javier, being a practicing Catholic, doesn't stick to the reverend's Protestant ways instead, telling him that "I'm sure there's priests who will happily take your confession", before making the Sign of the Cross and praying; in response, Swanson tells him that he (Javier) is doomed, possibly foreshadowing his demise twelve years later. Swanson also has a dislike for Catholics, as his conversation with Hosea shows, and how he refers to Brother Dorkins as a fine man in spite of being Catholic when telling Arthur about him.