Benjamin "Ben" Donovan is Juliet Sharp's ex-convict brother and a former crush of Serena van der Woodsen. He came from a middle class family in Connecticut and taught as an English teacher at the Knightley School, the boarding school that Serena attended prior to the series.
When Serena is in boarding school, Ben and Serena grew close, as she valued him as someone who took her seriously and genuinely cared about her taking advantage of her. It is when Serena met Ben that she reformed from the wild party girl to the caring person that she is today. They shared a mutual affection for each other, and while Serena wanted to pursue a romantic relationship with him, he gently declined due to their teacher-student relationship.
Unfortunately, rumors began circulating, partially started by Damien Dalgaard, that Serena and Ben were in a relationship. While visiting the school, Lily heard of the rumors and took drastic measures to ensure that no one would hear about it. Lily has Ben charged with transporting a minor across state lines and statutory rape, and was told that Serena signed an affidavit confirming that he did so. In order to keep this scandal out of the papers, he is offered a plea bargain which states that he will spend five years in prison. For this reason, Ben and his sister Juliet plotted against Serena, wishing for her downfall from social grace. Although desiring to harm Serena socially, he had no intention in hurting her physically, an intention that Juliet possessed. Ben later finds out in season four that Serena had not signed these papers, and that it was Lily who did this in order to get her daughter into Constance Billard with a clean reputation. Morever, Serena wasn't even aware of Ben's situation and visits him in jail at the end of "The Townie" once she does find out. Once Ben is released Lily tries to pay him off and make him leave town before more damage could be done to her family, something that he tried to abide by although not taking any of her money. Serena attempts to rekindle their old friendship but he hesitates and lies about his feelings to deceive her,.
Ben threatens Damien to stay away from Serena and her family (Damien 'befriended' Eric ), so Damien, being Damien, comes up with a scheme to have Ben sent back to prison. Eric has been going through a rough time and ultimately trusts and likes Damien because he feels he understands him, making Eric a quick ally. Dan cares about Serena and Eric approaches him. At W's party the trio frame Ben for punching Damien and call his PO and he spends a night in jail. Serena tries to stop him to no avail.
Dan tells Ben's PO the whole story (he didn't know that Eric actually punched Damien) and Ben comes back to the loft (where he's been staying with Dan). He and Serena develop a romantic relationship and it continues until his mother returns and steals Lily's papers that prove she forged Serena's signature and had Ben falsely arrested. Serena believes Ben did it after a few people influence her views and discovers he had his fellow inmates jump Howard Archibald and is upset. They later amicably stop their relationship. Lily goes to jail and clears all of Ben's possible charges, so he can lives his life the way he should have been able to.Ben also has an enemy in Damien Dalgaard because of three reasons. Firstly, he is the one who helped spread rumours of him and Serena at a bed and breakfast leading many to believe that they slept together and Ben's eventual imprisonment. Secondly, Ben still cares about Serena and does not wish for her nor any of her family members to be hurt so he cautions Damien to stay away from the Van Der Woodsens, something that Damien refused to listen to, and consequently Ben eventually threatens Damien with death.
Serena reignites their old flame and although at first Ben refuses to continue maintaining a close relationship with her, they later begin a romantic relationship, against the wishes of most.