|“|| Crowley: First impressions can be deceiving, Moose. For instance, I once thought of you as dull and plodding.|
Crowley: Oh, never mind. Bad analogy.
in Hell's Angel
Their first mutual adversary was Lucifer. Due to his previous experience with Ruby, Sam did not trust Crowley at all and tried to kill him many times. He did not develop much trust in Crowley unlike Dean when the Winchesters first met him. Crowley affectionately refers to Sam as "Moose". After Crowley's heroic death, Sam seems to have lost all of his resentment at Crowley, replaced with genuine gratitude and respect for his sacrifice, as he unhesitatingly acknowledges Crowley has changed greatly to Rowena and felt she should be proud that he ended up a hero in the end by sealing Lucifer away. In addition, Sam also honored what Crowley's last wish had been: to ensure Hell has no leader, by killing Kipling and threatening any demon wanting the title of the Ruler of Hell with death.
Season 5 Edit
The brothers infiltrate his house but find themselves rather welcomed, with Crowley giving them the Colt as well as more ammunition. The brothers then attempt to use the Colt against Lucifer, but when the Colt proves ineffective, they both blame Crowley for providing them with false information.
Crowley approaches them weeks later, having barely survived being hunted down by other demons. Sam makes a move to stab Crowley with the demon-killing knife, but Crowley insists he too didn't know the Colt wouldn't work. He offers them help in locating Pestilence, having somehow found out that they are after the Four Rings worn by the Four Horsemen.
Crowley convinces Dean to leave Sam behind while the two of them hunt down a certain demon, at first claiming it was because he didn't like Sam due to Sam's tendency to constantly try to kill him. It is later revealed that said demon has a history with Sam, and Crowley wanted to avoid the plan being jeopardized.
After they obtain Pestilence's ring, Crowley continues to aid the Winchesters in finding Death. By this point, Sam seems to trust Crowley more, but still remains wary of him.
Season 6 Edit
Sam returns from Lucifer's Cage through unknown means, and instead of going back to Dean, he resumes hunting and also starts working with the Campbells, unaware that by doing so, Sam is also working for Crowley, who is using them to capture monsters and Alphas.
When Bobby needs help getting his soul back from Crowley, Sam and Dean fly to Scotland and dig up Crowley's bones. While Dean is tempted to just kill the demon, Sam stops him, saying that a deal was a deal. Crowley stated that he didn't need Sam fighting his battles before taking his bones and leaving.
When Sam does find out Crowley holds his soul, which he claims to be in possession of, as ransom, forcing the Winchesters to continue working for him.
Eventually, Sam works with Dean, Meg and Castiel in an attempt to kill the demon. He and Dean also convince Crowley to return Bobby Singer's soul by locating Crowley's human remains. When the demon proves to have survived an attempt on his life, Sam and Dean begin hunting for him, also to stop him from opening Purgatory.
Sam later learn that Crowley never had his soul nor was he was the one who brought him back but Castiel who was working with Crowley. Sam was angered his friend sided with the demon and turned on him.
Season 7 Edit
In Season Seven, Time for a Wedding! Crowley appeared before to the Winchesters. Sam was shocked to see him, Crowley congratulates Sam on his wedding and reveals he ordered his demons not to interfere with the Winchesters as they fight against the Leviathans. Sam was surprised by his support in their endeavors.
When they need his blood for the weapon that can kill Leviathans, Sam reluctantly allies with Crowley again. Despite this, Sam still doesn't trust Crowley. After Dean kills Dick Roman and disappears with Castiel, Crowley appears and taunts Sam about being "well and truly on your own" and kidnaps Kevin Tran, refusing to tell him where Dean and Castiel are.
Season 8 Edit
Shortly after Dean's return from Purgatory, Sam works with him to try and seal up Hell forever, so they could be rid of the demons, including Crowley. As part of the trials necessary to complete this task, Sam attempts to turn Crowley human in the episode "Sacrifice", even saving him from Abaddon, but stops at the last moment at Dean's insistence.
Season 9 Edit
To save Sam from Gadreel, Crowley offers to possess Sam in exchange for his freedom. Entering Sam's mind, Crowley informs him of his possession and helps him overpower the angel before expelling him.
Sam reluctantly works with Crowley to stop Abaddon. After Dean kills Abaddon, Sam lets Crowley go free but refuses to help him remove a devil's trap bullet, saying that letting him live should be enough for him. He gets angry when Dean works with Crowley to hunt Metatron and sends him away.
Season 10 Edit
Sam yells at Crowley when he finally gets him on the phone and learns that he is sending demons after Dean. Crowley lets Sam track Dean down to force him to get moving and helps Sam capture Dean in order to stop him as Dean as a demon is completely out of control. Sam hands him the First Blade in exchange.
Season 11 Edit
|“|| Crowley: Makes your flesh crawl, doesn't it Moose? I get it. I'm the King of this place. It's still not my cup of tea.|
Sam: I don't know, Crowley. I'd say it suits you. Dark. Empty.
Crowley: Fascinating; the utter contempt, when I'm in the midst of saving the Winchester's bacon, again.
— Crowley and Sam
in O Brother, Where Art Thou?
Sam experiences mysterious visions which beckon him to seek out Lucifer. After Dean relents, the brothers seek out Crowley and Rowena's help. The plan was initially to wait for Dean to come back after checking out a crime scene, but Sam decides to go ahead without him and travels to Limbo, where the trio meet Lucifer.
Unfortunately, Rowena had been working for Lucifer all along and Sam ends up trapped inside a cage with his former torturer. Crowley thus calls Dean and informs him of Sam's predicament. With Dean's help, Crowley manages to force Rowena to cast a spell to send Lucifer back to the Cage, using a witchcatcher. Once Sam is safe, Crowley orders him and his brother to get out of Hell.
Sam and Crowley do not hear from each other for a couple of weeks. A demon informs Sam that Crowley has become Lucifer's bitch-boy, and Crowley himself, upon escaping Lucifer's clutches, tells the brothers of some of the things Lucifer did to him. Both Sam and Dean express joy at the Crowley's suffering.
With Crowley and Rowena's help, the brothers set up a trap for Lucifer with the intent of expelling him from Castiel. Their combined efforts accomplish nothing, aside from Crowley getting momentarily trapped inside Castiel until Sam expels him using an incantation.
Weeks pass by again before Sam and Crowley see each other again. God reveals himself to the brothers and devises a plan to use angels, witches and demons as part of their attack against Amara. The main members gather at a warehouse, though Sam and Crowley do not converse.
They remain on the same side following the attack's failure. While Crowley and the rest feel hopeless, Sam encourages them to think up another plan, and they end up using a Soul Bomb as their last resort. Dean is selected to carry the bomb to Amara, while Sam and Crowley and the others wait for the results inside an abandoned bar.
When the sun returns to full glow, Sam and Crowley along with everyone else deems the mission complete, and Dean to be dead. The hunter and demon therefore, go their separate ways.
In "American Nightmare", Sam is informed by Dean that Castiel and Crowley are working as a team to try and hunt down Lucifer. In "Rock Never Dies", Sam and Dean go to Los Angeles to help the pair prevent Lucifer from hosting a concert and then killing the fans.
Sam joins Dean in chasing the fans out while Crowley joins Castiel in confronting Lucifer. Together they are successful, and Lucifer departs from his vessel towards a new, more influential vessel. Sam meets up with the team outside, and he and Dean both take note of the state Crowley is in.
Sam continues to hunt down Lucifer with Crowley in "LOTUS", during which he and the others find out that Lucifer's latest vessel is the President of the United States. While Sam, Dean and Castiel meet with British Man of Letters Arthur Ketch and receive a weapon that can expel Lucifer from his vessel, Crowley fulfills the task of retrieving his mother so she can banish Lucifer back to the Cage.
Sam uses Ketch's tool to expel Lucifer from Jefferson Rooney, and believes that once Rowena cast the spell, Lucifer has gone back to Hell again. Crowley leaves Sam and Dean behind with the unconscious President while he takes his mother some place safe. When Crowley finds out a while later that Sam and Dean had been arrested by the US Secret Service, he learns from his government spies that the prison Sam and Dean are being held is top secret information.
Regardless of not knowing where the brothers are, Crowley has high hopes that they will make it out of prison alive with the need of assistance.
During Stuck in the Middle (With You), Crowley appeared to the Winchesters and Castiel as they fought Ramiel. Crowley informed them of the threat but refused to help them. Despite that, he tried to stop Ramiel from killing the Winchesters but is thrown through a barn for his attempt. Sam was shocked at this and even concerned about the unconscious Crowley. Sam seemed grateful that Crowley saved Castiel from the poisonous effects of the Lance of Michael.
Crowley and Sam do not hear from each other until the brothers request to meet Crowley's son Gavin MacLeod. Crowley refuses their request, but this doesn't stop Sam and Dean from getting help from Rowena. Even worse, Sam and Dean plan to send Gavin back to his own time because his arrival in the present had let a ghost to go rampant and kill various teachers.
Rowena stops Crowley from intervening, and Sam and Dean successfully send Gavin back in time, allowing Gavin to abord his ill-fated ship and die.
Crowley holds a grudge against the brothers for this act, as shown when Sam and Dean contact Crowley over a rogue hellhound. Crowley expresses his disdain for the murder of his son, but he helps them anyway because the rogue hellhound happens to be Ramsey, the oldest hellhound currently alive. Despite Crowley's help, it is Sam who defeats and kills Ramsey.
Later on, Sam and Dean contact Crowley over another rogue hellhound that has been killing hunters, including a friend of theirs. Crowley denies any involvement, and claims he had been cuddling with the hellhounds the night before. Crowley is lying however, since the rogue hellhound was a gift he gave to the British Men of Letters as part of their truce.
Sam gathers a team to infiltrate the British Men of Letters compound, since he knows they are the ones behind the murders. The team is successful in executing many operatives, and Sam corners the leader, Doctor Hess. Hess tries to offer help in dealing with Lucifer, whom she reveals has escaped imprisonment because of Crowley. Indeed, all this time Sam had thought the archangel had been sent back to Hell, but Crowley had perverted the spell and kept Lucifer in his palace for revenge.
In "All Along the Watchtower", Sam informs Dean and Mary Winchester of the news. Sam is unhappy when Crowley shows up to confess about his blunder. When Dean nearly kills Crowley for his actions, Crowley begs Sam for help as the latter tells Dean that Crowley could fix his mistake, which relieves the demon. However, Sam mentions his intention to kill Crowley if not as the latter's smile fades. Crowley then offers - much to Sam's confusion - a willingness to seal the gates of Hell so that Lucifer can never escape again. The three thus join forces in confronting Lucifer near a beach, since it is the location where Lucifer's unborn child, whom Lucifer had conceived with the President's mistress, will be born.
The trio meet Castiel there, and learn from that the child had opened up a portal leading to an alternate reality. The four agree to lock Lucifer on the other side of the portal. Crowley chooses to be the spell's caster, which will require the caster's life as a final ingredient. Once Lucifer is inside the portal, Crowley stands between the Winchesters and Lucifer and bids the brothers farewell, before stabbing himself. Though shocked, Sam proceeds to drag his brother out of the portal.
In Various & Sundry Villains, Sam tells Rowena about Crowley's death and tells her she would have been proud as he sealed Lucifer away. He also openly admits that Crowley has changed greatly from his interaction with the Winchesters, showing that he respected Crowley's selfless sacrifice.
In the season's premiere Stranger in a Strange Land, Sam finds Kipling to be much worse than Crowley and refuses to make a truce with him. He then kills Kipling and threatens all the Demons who would dare to be the Ruler of Hell with death, henceforth fulfilling Crowley's wish of depriving Hell of a leader. His actions can be presumed to be done in honor of Crowley's heroism by granting the deceased former King of Hell what he wanted to do but did not got the chance to do.
- Mark Sheppard revealed that his favorite insult is "Moose", which is Crowley's nickname for Sam.
- Mark, like the rest of the cast, is a target of Jared Padalecki's pranks. Mark attempted to get back at Jared during the filming of "Hell's Angel", but found he was unsuccessful.