Agent Daniel Sousa was one of the agents summoned by Roger Dooley to meet and discuss the possible betrayal of Howard Stark to the United States. During the meeting, Sousa heard Krzeminski doubt Peggy's virtue. Sousa then asked him to apologize to Carter; Krzeminski simply decides to mock him. After the meeting, Peggy reprimands Sousa since she could defend herself.
He later was excluded from a meeting between the Chief Dooley and the agents Yauch, Thompson, and Krzeminski.
Days later, Carter learns that Sousa had some pictures of a blonde woman in La Martinique. She tries to get them but without success. Later, Sousa watched as Thompson beat Miles Van Ert during the interrogation. When Thompson learned that Sheldon McFee was involved, Sousa already had the address. That night, while the other agents were discussing the possibility that a woman was involved in the death of Leet Brannis, he found a key in the dirt.
He and Jack Thompson went to Howard Stark's mansion to ask some questions to Edwin Jarvis after learning that a license plate that belonged to Howard Stark was in the wreckage of the Roxxon Refinery. Sousa took notes while Thompson interrogating Jarvis. That night, he and Krzeminski received an anonymous call. The anonymous caller informed them the location of Stark's weapons. Although the information, Sousa showed skeptical, instead Krzeminski was very excited. When they arrived at the scene they found the weapons but also Jerome Zandow unconscious. Krzeminski then called Chief Dooley to report the finding. The next morning, Sousa felt that the anonymous caller was involved in the murders of Ray Krzeminski and Jerome Zandow.
A few days later, Sousa returned to the dock where they found the weapons. Here he finds a witness. Sousa takes him to New York Bell Company to ask some questions. As the witness said nothing, Thompson had to intervene because the witness did not want to cooperate. After the witness give them information, Thomson told Sousa that not all veterans returning from war for a hug.
While Peggy Carter is changing for the mission in the men's locker room, he notices that Carter has a gunshot wound on her shoulder. Days later, Sousa see the pictures of blonde woman in La Martinique and discovers that the woman has the same scar that Carter.
Sousa informed Dooley that Peggy Carter was the mysterious blonde woman from La Martinique. Dooley sends Sousa and Thompson to capture Peggy Carter. Later, when he saw Thompson lying on the ground; he asks Carter to surrender but she knew he was not able to shoot her. As she was right, he leaves her go. Sousa and Thompson went to Griffith Hotel to catch Carter. They went to Angie's room to ask her some questions. As Carter was out of the room, Angie pretends to cry for the purpose of annoying Thompson and Sousa. Eventually, Thompson and Sousa captured and takes Carter to the New York Bell Company for questioning.
Agent Sousa was one of those responsible for interrogating Peggy Carter. Sousa was very disappointed because he appreciated Carter. He was later present when Carter confessed the reason why she helped Howard Stark. Dooley then sends him and Thompson to investigate the building crossing the street. Thompson told Sousa his experience in Belarus. Thompson also told him that if he sees the woman shoot to kill. Sousa found out the place where Underwood and Ivchenko communicated before facing the Soviet assassin. Sousa later saw as Chief Dooley sacrificed himself to save the lives of their subordinates.
Carter, Thompson, and Sousa went to a cinema theater where a slaughter had occurred. Here, Sousa found the container of Item 17 and accidentally inhaled it. He attacks Thompson and Carter before being knocked out. Later, Carter explains to him what happened. Sousa and the others went to Stark's secret hangar. He pretended to be brainwashed in order to arrest Fennhoff. The next day, Sousa was present when his co-workers got a standing ovation to Carter. However, Thompson received the credit from the President. Sousa sought that Carter received the credit but she was no more interested in what others thought. Sousa leaves out his shyness and asked Carter to have a date, she replied that on another occasion but she smiles thinking about it.