Carter Walton came to Los Angeles to visit his adopted brother, Marcus Walton, who had also been adopted by the Forresters. Marcus proudly introduced Carter to his family, especially his wife, Dayzee Leigh. When Marcus bragged about Dayzee's organizational skills, he ran across some mysterious adoption papers. Dayzee admitted she had long ago helped a woman named Maya Avant give up her baby for adoption since Maya was being wrongly jailed for a crime. Now Maya was back and wanted her baby returned, and Dayzee felt she might be in trouble since she had allowed attorneys to handle the adoption and didn't know if money had changed hands. Carter studied the papers and informed Dayzee that Maya had a legal right to know who had adopted her baby.
Carter helped Marcus and Dayzee search for the adoptive family of Maya's daughter, only to find out that they had all died in a car crash. Later, Carter met Marcus' cousin, Rick Forrester. Rick explained that Forrester Creations had been having some problems with patents and counterfeit designs, and Marcus suggested that Rick hire Carter, since that was Carter's area of legal expertise.
Carter met Maya and asked her out, not knowing that Maya had liked Rick until she found out Rick had withheld his identity as a Forrester. Carter brought Maya to the Forrester mansion for a dinner party and realized Maya was uncomfortable seeing Rick with his girlfriend, Caroline Spencer. Caroline, jealous of Rick's interest in Maya, wanted Carter to continue pursuing Maya so she would forget about Rick. Carter was hopeful about Maya, but wary of Caroline's manipulations.
Carter met Steffy Forrester and Liam Spencer, who were planning their wedding. When Carter informed them that he was licensed to perform weddings, Liam and Steffy snatched him up to preside over their ceremony, which featured Steffy riding up the aisle on a motorcycle wearing a black dress/suit ensemble. The wedding afforded Carter an opportunity to meet Justin Barber, Marcus' biological father.Caroline convinced Carter, Marcus, and the other male execs at Forrester to strut their stuff on the runway, modeling sleepwear in a fundraiser for Caroline's cancer foundation. Maya was impressed with Carter, and they flirted. But when Carter walked in on a heated conversation between Maya and publishing magnate Bill Spencer, he suspected something was wrong. Carter eventually encouraged Maya to admit that Bill was blackmailing her in an attempt to keep her away from Rick and clear the way for Caroline, who was Bill's niece.
An aspiring actor as well as a lawyer, Carter was thrilled when he was cast as the lead of Room 8, a new web series. Rafael, the show's producer, surprised Carter by casting Maya as his leading lady. Still enamored of Maya, Carter kept his feelings in check as his character, "Lance", began a sweet romance with Maya's "Scarlett." But when Rafael showed a preview at Rick's Fourth of July party, the footage had been edited to appear much steamier. Carter flinched when the scenarios and dialogue became increasingly cheesy, but the eroticism of them made him hot for Maya to the extent he suggested they sleep together for real, saying Rick would never have to know. Maya gently rebuffed Carter, who was shocked when Maya discovered that Caroline had been pulling strings behind the scenes in an attempt to get Rick to dump Maya. Rafael made things up to Carter and Maya by having them reshoot Room 8 the way it was originally written.
Carter consoled Maya when Rick couldn't make it to the premiere screening of Room 8. Carter was encouraged when Maya accepted his offer to celebrate with a bottle of wine at her place, where they ultimately fell into a passionate kiss. But when Maya refused to let things go further between them, Carter slept on her couch. Later, Maya felt guilty and wanted to tell Rick. Carter insisted that all they had done was kiss and felt there was nothing to apologize for. After the truth of the kiss led to Rick sleeping with Caroline, and Maya breaking up with him, Carter gave Maya his full support. He soon came to Maya with an idea for a Room 8 script, which they read as Scarlett and Lance, but was really Carter's unique way of proposing to Maya. Carter was happy when Maya accepted, and they made love to celebrate the engagement.
Making wedding plans, Carter remained blissfully unaware that Maya still had feelings for Rick. When Maya admitted that she missed working at Forrester, Carter went to Rick and asked him to hire her back as a spokesmodel, earning Maya's gratitude. At a Forrester Thanksgiving dinner that doubled as an engagement party for Caroline and Rick, Carter was called upon to officiate at their impromptu wedding ceremony, pleased that Maya had given them her blessing. Continuing to oversee legal matters at Forrester Creations, Carter was also asked to preside over the remarriage of Ridge Forrester and Brooke Logan, which came to a halt when Brooke's sister, Katie Logan, fainted as Carter read a poem to the bride and groom. The guests wondered when Carter and Maya were going to tie the knot themselves, but Maya simply stated that she liked being engaged.Carter was concerned when Maya came to him with a recording she had made of Oliver Jones, who admitted only dating young Aly Forrester because of her position in the family. As a lawyer, Carter reminded Maya that recording someone without their consent was illegal; as a fiancé, Carter couldn't understand why Maya was so preoccupied with Oliver. Later, Carter was furious to learn that Maya had come on to the married Rick in the Forrester steam room. Maya insisted that she just had to be sure the door with Rick was closed, but Carter broke off his engagement to Maya, barely being civil to her when they ran into each other in public.