Jack is Emily's childhood friend, and the (half-)brother and legal guardian of Declan Porter following their father's sudden death. He becomes the boyfriend and later husband of the real Emily Thorne (now named Amanda Clarke). He takes over The Stowaway, his father's bar, after his death. Jack is one of the three men for whom Emily has feelings (the others being Daniel and Aiden), and Jack holds feelings for Emily in return. These feelings culminate in them kissing after watching Sammy, the dog owned by both of them at different points in time, die. However, they are unable to get closure from the kiss because of Amanda's return. In Season 2, Jack becomes a father when Amanda gives birth to their son, whom they name Carl David Porter, after Carl, Jack's father, and David Clarke, Amanda's "father". On their honeymoon, they are held hostage by Nate Ryan; though Jack manages to escape, Amanda is killed on their boat by Nate despite Emily's attempt to save her. Amanda's death causes Jack to seek revenge on Conrad for ordering her murder, and he grows distant from Emily and Nolan when he believes they are lying, and when Emily becomes re-engaged to Daniel. To this end, he works together with Ashley Davenport to destroy Conrad's gubernatorial campaign, though Conrad soon learns of their deceit and attempts to kill Jack by leading him to Grayson Global, where The Initiative's bomb plot is being set in motion, although Jack escapes before the bombing. Declan, who was in the building when it exploded, dies, further devastating Jack and pushing him to attempt to assassinate Conrad at the election. Before he can shoot, Emily stops him by revealing her true identity. In season 3 Jack returns to the Hamptons, six months after learning the truth about Emily, and gives Emily an ultimatum to end her plotting by the end of summer, or he will expose her secret. Charlotte and Jack form a good friendship during the season. Jack later meets and begins a relationship with Margaux LeMarchal. He also learns that his father kept his mother's identity a secret from him.