Still in the second season, Chuck loses his father Bartolomeu in a car accident, and blames his stepmother because he believes she has an affair with the boyfriend of his youth (Ruffles). Blair reveals to Chuck that she loves him but he rejects her. In the episode "Remains of the J", he stays with Vanessa to envy Blair and Nate, who are back together. In the last episode of the second season, Chuck reveals to Blair that he loves her, after much discussion and confusion. The final scene is accompanied by the song Season of love by the American group Shiny Toy Guns. Chuck surprises Blair in the lobby of her building, where he delivers gifts and finally says "I love you too". Finally, the most complicated couple in the series makes up, and the season ends with the two kissing. Chuck and Blair form the most beloved couple in the series, overshadowing other characters, such as Dan and Serena. Blair and Chuck are so acclaimed that they have several fan clubs, as well as hundreds of communities on dating sites dedicated to the couple. They are known by the nickname Chair (Chuck + Blair) around the world.
In the third season, Chuck loses the lifestyle he had, where he was only interested in money, women and sex. He's dating Blair, so he spends most of his time taking care of her and the business his father left behind. Trying not to live in Bart Bass' shadow, Chuck buys The Empire Hotel and tries to do business his own way. This season, Chuck discovers that his mother is still alive and tries to form bonds, but is disappointed to discover that she is cohabiting with his paternal uncle and enemy Jack Bass. In his recurring games with Blair, the relationship begins to be in danger due to the lack of trust between them. After completely betraying Blair's trust, who would do anything for him, exchanging her for his beloved Hotel, the relationship ends. Chuck does everything he can to win Blair back, but when he loses hope he gets involved with Jenny Humphrey. When Blair is ready to forgive him, she discovers what happened and ends the relationship once and for all. Hoping to save the engagement ring he would give to Blair in a robbery, Chuck is shot in the last episode of the season.
In season five, Chuck loses Blair to Louis. Blair and Chuck relapse, but Blair ends up pregnant with Louis. Chuck does everything to have Blair again, and when they are about to be together, they suffer an accident, in which Chuck is on the verge of death and Blair loses the baby. Blair makes an oath that she will marry Louis if Chuck survives, and he does. During this time, Blair gets even closer to Dan. Blair almost doesn't marry Louis, as she was caught declaring herself to Chuck on her wedding day. However, he takes her back and the marriage continues. After Blair discovers that the prince is not what she thought, Blair ends up getting involved with Dan, and comes between him and Chuck Bass. However, at the end of the season, she chooses Chuck.
In the sixth season they make a pact to be successful, before getting together. Which ends up happening due to the death of Chuck's father in the penultimate episode. In the last episode, due to the escape from the police, Chuck and Blair get married, to the delight of the couple's fans. After five years they have a son named Henry, who is the first Waldorf/Bass heir.