In the season premiere, Greer alongside Lord Castleroy joins the rest of the court to hear Mary's announcement about the plague. During the speech she notices Castleroy's daughter, alongside Leith. She tells Lord Castleroy that she isn't jealous but worried. When he asks why she tells him about the vow Leith made to rise and find happiness with another all to rub it in Greer's face. After the gathering she and Kenna find Mary who tells them that Lola is giving birth and that there are some complications, before leaving. She later talks to Leith about him being with Yvette. They argue about his relationship with Yvette and his vow to her. He tells her he was on his way to meet Yvette and Greer begs him not to go.
In Drawn and Quartered, Greer and Lord Castleroy mourn the loss of Yvette. Lord Castleroy and go to Leith's home. Castleroy confronts him about Yvette's death; he believes that Leith knowingly got into a relationship with his daughter because of who she was, because of her proximity to Greer as Greer told him of the revengeful vow that Leith made toward Greer. He the punches Leith in the face and warns him to stay away from his family including Greer.
Later, Greer seeks out Leith at his home and admits that she feels like she betrayed him by telling Castleroy about his idle threats. Greer believes that she's poisoned everything, apologizing to him and urging him not to blame himself for Yvette's death; however, she admits that she regrets loving him and that she needs time in order to move on from him. When Greer returns from Leith's, she admits to Castleroy that she went to see her former lover, though she assures him that Leith is wracked with guilt over what happened to Yvette. Castleroy, for his part, is more worried about Greer's loyalty, believing that she chose his finances rather than him and that her heart still resides with Leith. As such, he's planning to go on a business trip that will involve seeing his children and informing them of Yvette's death.
In Coronation, Greer attends the celebrations at the Tent City when she and Mary approach Louis. The two realise that he is accompanied by a courtesan, which Greer judges him openly on. She later discusses the shortage of grain along with Mary. She along with the rest of people at court, attends Mary and Francis' Coronation.
In The Lamb and the Slaughter, when Lola, Kenna, and herself are sitting outside together, she and Kenna give Lola gifts for her baby. When Narcisse arrives with Estelle, it brings the three girls to a pause before they approach the two. When asked by Narcisse, she introduces herself and Kenna to him. When the two leave, Greer and the rest of the girls discuss how nervous Estelle looked. Later during a walk with her friends, Mary announces the news of her pregnancy to which Greer replies is wonderful news. The four then propose a toast to Mary. She's asked by Lola if she's heard from Lord Castleroy. She replies that she's only heard the most formal and evasive responses to her letters. She tries to comfort Lola by telling her that she'll get through her situation and find love again. She and Kenna later take a stroll onto the grounds. They stumble upon Leith. Kenna tries to show her that she does have a choice in the matter of who she is to marry. She tells Greer that she can't live for desire because its nothing to build a life on.
Later that night, at the bamquet she's asked to dance by Louis and accepts. While switching partners during the dance, she's partnered with Leith. He tells her that if they are to run into each other, there is no reason for anything to be awkward between the two of them. In the middle of their dance, when they look into each other's eyes she tells him she has to go. The next day, she misses the christening to go tell Castleroy that she wants to marry him. Later that night, she lets him know why she wants to be with him and not with Leith. She tells him all the things she loves about him and that she wants to explore their relationship. They kiss and she offers him her virtue.
Greer's wedding is soon to come in Blood for Blood. Mary talks to Greer about her wedding day and Greer says she isn't sure about the big wedding. Gemma, Castleroy’s youngest daughter runs up and she introduces her to the ladies and Kenna says those are her children now too.
Later, Greer, Kenna, and Lola complain about the heat and talk about the book the day before Greer’s wedding. They discuss that she will soon be a mother of four. Kenna hops into the fountain and Greer joins her. Lola holds their goblets but then Greer splashes her. Lola splashes back and Greer falls over into the fountain and drenches herself. She says she has to change before her mother finds her. Leith finds her on her way back to the castle and she says she knows she looks like a drowned rat. He asks her if Castleroy has spoken to her and she says no. He says there is something she needs to know about her future husband – a secret. She asks why he’s telling her and he says for more than one reason. He tells her to ask him about this morning before she marries him. He says to do it for herself, not him. Castleroy tells Greer that he was at the Protestant service that morning. He says he’s been looking for meaning in life. She is scared of what him converting could do to him and his children. He tells her that he loves her but won’t give up on his beliefs. He says if she ends this now, he will still fund her sister’s dowries. He tells her if she does marry him, they will be full partners except this disagreement over faith. He tells her that he hopes he will see her at the altar tomorrow.
Castleroy waits at the altar and everyone stands and stares. Greer appears at the end of the hall and Castleroy walks to her. She shrugs off her cloak and has her bouquet. She walks to her husband to be and smiles warmly at him. Greer looks nervous but committed. Leith leaves. At the reception, Castleroy asks Greer what changed her mind. She says she’s always wanted safety but says she admires that he stands up for his convictions. He tells her that he’ll protect her and she says she’ll protect him. The children run up to dance with them and she happily twirls her new step-children.
Greer returns inThe Prince of the Blood. During Claude's welcome, Mary spots Greer trying to sneak by, and when she goes into her room, she learns the truth: Greer and Castleroy were attacked during their wedding tour after Castleroy didn't take mass. Greer admits to Mary that she married a Protestant but hasn't converted. Mary tells her about the law the nobles want signed to identify the Protestants. Greer is shocked and says they’ll be persecuted. Mary says she’ll try and persuade Francis not to sign it. By the end of the episode, Greer tells Mary that Francis signed the edict.
As Greer adjusts to her new life with Castleroy in Acts of War, he invites his Protestant friends to their home and she realizes that he’s hoping she’ll consider converting. Greer agrees to think about becoming a Protestant, admitting that she thinks it best if their children are raised in a united house. The night of the Saint Nicholas dance, Greer and Castleroy receive news of the Protestant extremists sneaking into the castle. Jacob, a Protestant, rushes to Castleroy’s house to help him and Greer escape to safety. It’s then that Castleroy and Jacob realize that money Castleroy donated to help build a school went instead to pay for the extremists assassins, much to Greer’s horror.
In Mercy, when Greer along with Kenna and Lola visit Mary, they are shocked to hear from her that she was raped. As they try to comfort her, she backs away as she prefers not to be touched. Greer urges Castleroy to separate himself from Protestantism before it is too late. She fears that he will hang for his part in the assassination attempt. Leith comes to warn Greer that his job involves rounding up Protestants, Castleroy is captured. Later, Castleroy is taken and he tells Greer not to get involved because he will be okay. Leith manages to get Castleroy out by going to Francis and gives up his land. While Castleroy decides to get as far away from court as possible, Greer stays.
In Getaway, Greer goes along with Mary, Leith, and Conde to Conde's estate. When they arrive, a party is being taken place and they meet Conde's brother, King Antoine. Antoine welcomes them and talks Mary into staying for the night and attending his party as the guest of honor. When things start to get too sexual at the party, things become awkward between Greer and Leith. Greer and Mary decide to leave the party before they’re selected by Antoine. Greer assumes that Mary is upset by the improper party they’ve left but she’s not over everything that happened to her, and can’t stand even a simple courteous touch from a man. Greer promises she’s strong and she’ll recover. Mary feels like she’s sleepwalking and cries as Greer hugs her. The next day when heading back to the castle, Mary tells that she was able to touch someone and connect and doesn’t want to be distant anymore, including from Francis.
Rumors about Greer's husband financed the protestant radicals begin in Banished. Mary questions Greer's whether there’s any truth to the rumors and Greer lies to her, saying that it's not true. Leith comes to Greer and she admits the truth that the rumors are true but her husband thought he thought the money he gave was being used to buy a school. Greer teams up with Leith to search for anything that would link Castleroy and Greer to the radicals. They meet with the accountant and tells Greer that he has hid Castleroy's personal ledger. However, during a party, the guards come in and tell Mary and Francis that the ledger has been found. The guards take Greer and put her in a dungeon. When Mary comes to see Greer, she is informed that her life has been spared but her title and land are being stripped from her as is her position as Mary’s lady in waiting.
In The End of Mourning, Greer has been staying at the village inn ever since she was banished from court. She is visited by Kenna and Lola. Greer has made no plans for what she’s going to do but has been drunk regularly. Lola gives Greer some money to get by but Greer refuses to go back to Scotland. She thinks she could find work as a lady’s companion, due to her noble birth. They hear noise next door and Greer goes to quiet her neighbor. During the night while Greer is having dinner, she's propositioned by a nice man in the inn common room. He thinks she's a prostitute and she's lectures him then offers to arrange the services of her next door neighbor. The next day, Greer is interviewing to be a lady’s companion for a Hungarian countess when Sharlene arrives and tells her that the man she sent, drugged her and cut off her hair. After seeing this, the Hungarian countess decides to not hire Greer.
In Forbidden, Greer repays Sharlene with a wig after she lost her hair. Greer also arranges for Charlene to go to Kenna's party and meet new, high-class clients. Sharlene comes back with enough money to cover two months rent and begs Greer to help her and the other girls attend more parties and make more money. Greer agrees to this and becomes a Madam.
In Tasting Revenge, Greer reunites with Leith. He brings news that Castleroy’s been imprisoned for treason. His wealthy friends had his sentence commuted so he’ll live but he will possibly never leave prison. Leith is worried about her but she says she’s making her way. She thanks him for bringing the news and quickly leaves. Sharlene questions Greer on her relationship to Leith. Greer sees Leith again and they begin a friendship. Greer soon defends one of her friends from a dirty old man. Leith is surprised to hear of Greer's new occupation and wants her to get away from the prostitute life style. She refuses and doesn't care whether he likes it or not, not needing his approval. She returns to her room and starts to cry. Leith comes in and tells her that he doesn't care what she does or what they say because he wants her. They kiss and begin to have sex.
In Tempting Fate, Greer's moment with Leith is interrupted when Sharlene busts in because she has a customer downstairs and nowhere to “ply her trade” because one of the other girls is using her room to do so already. Leith isn’t thrilled by how often they're interrupted by Greer’s employees and wonders why she hasn’t grown tired of this yet. She’s saving to rent a townhouse, but until then, they’re stuck at the inn. Leith starts to ask about marriage but Greer reminds him that she is already married. He thinks she could have the marriage annulled with the help of their friends to get the Vatican’s approval. Greer wants none of it and for him to leave it alone. She’s always loved his decency, but all she can offer is herself.
In Reversal of Fortune, Greer has purchased a grand townhouse to open her brothel in and is ready to entertain some merchants. Later, when Claude arrives at the brothel and starts to cause a ruckus, Greer tells Leith to get Claude out of there.
In Abandoned, Greer is visited by Lola and Kenna in her new place. She tells them that the reason for her new success is that she is running a brothel for prostitutes. Lola and Kenna are surprised but happy that Greer has found independence. They toast to her new success.
Leith proposes to Greer in Fugitive. She turns him down because she doesn’t want to give up being a Madame. He told her he would give her a respectable life and a family but she insists that she wants to keep her business and her independence. For her safety, she doesn’t want to rely and depend on a man again. Leith ends their relationship for good and walks out.
Greer helps Mary in Burn. Mary asks Greer to have the prostitutes to blackened their hands with ash to cause a panic and scatter Conde's troops in order to help Francis and save France. The plan was a success and Mary thanks Greer for her help.