Born in Lisbon, Santos played youth football with three clubs, including Casa Pia A.C. from ages 13 to 19. He spent his first seasons as a senior in the lower leagues, scoring a career-best 17 goals in 2009–10 to help the team promote to the third division.[2]
Subsequently, Santos moved to the professionals after signing with Leixões S.C. from the Liga de Honra. In his second year at the Estádio do Mar, he started in 23 of his 27 appearances (four goals) and the side finished in 11th position.
In the summer of 2012, Santos joined Vitória de Setúbal, making his debut in the Primeira Liga on 19 August of that year by coming as a 68th-minute substitute in a 2–2 away draw against C.D. Nacional, where he won a penalty and was also booked.[3][4] His first goal in the league arrived on 4 November, when he played 79 minutes and helped the hosts defeat Sporting CP 2–1.[5]
Braga
Santos moved to S.C. Braga also in the top tier in June 2013.[6] Before the end of the transfer window he was loaned to Romanian club FC Astra Giurgiu, and scored to cap a 4–0 win at FC Oţelul Galaţi on his 15 September debut after coming on at half time for Gabriel Enache.[7] Having made just three more appearances in all competitions, his loan was terminated in December.[8]
After returning to his parent club, Santos helped to consecutive fourth-place finishes and scored a total of 12 goals in the process.[13][14] On 22 May 2016, he replaced Josué for the last minutes of regulation time in the national cup final (2–2 draw), and converted his penalty shootout attempt in a 4–2 victory at the Estádio Nacional.[15]
Santos scored his first goal for the team on 24 March 2018, concluding a 3–1 home victory over D.C. United.[21] It was his only of the campaign, and he was sent off on 5 May in a goalless draw at Seattle Sounders FC for a kick to Alex Roldan's face.[20][22] The Crew would go on to make the playoffs, ultimately losing to the New York Red Bulls in the Conference semi-finals 3–1 on aggregate.[23]
Asked about his performance throughout the year, Santos replied: "Individually, it was not a poor season but I expect to score more goals. I always work for the team and I give my best for the team, to help my teammates. I think I had a good season but I was expecting to score more goals, for sure."[23]
2019 season
During the 2019 season, Santos recorded best professional figures of 11 goals from 33 games,[24] while playing both as a winger and stepping in as an attacking midfielder for the injured playmaker Federico Higuaín, who had suffered an anterior cruciate ligament injury.[25] On 28 July, he scored twice in a 3–2 away defeat of the New York Red Bulls.[26] However, his side would struggle mightily due to injuries across their entire roster and would miss out on the playoffs.[27]
2020 season
Santos moved back to winger for the 2020 season, and scored eight goals and assisted on seven more in 26 matches across all competitions as his team won the MLS Cup for the first time since 2008, making him the first Portuguese player to earn a medal in the tournament; he missed the final against the Seattle Sounders due to a positive COVID-19 diagnosis, however.[28] The day after the victory, his contract option for 2021 was exercised.[29]
Following the return of Valenzuela, Santos was pushed higher up the pitch, resulting in a one-goal, two-assist performance in a 4–0 victory against Inter Miami CF on 16 October.[35] In December, he signed an extension with an option for 2023.[36]
2022 season
With Columbus losing their first-choice left-back to a free transfer over the off-season, Santos became the starter,[37] with his lone goal coming from a free kick against D.C. United on 30 April.[38] At the end of the season, he was not retained and thus became a free agent.[39]
D.C. United
On 21 November 2022, it was announced that Santos had signed a two-year deal with D.C. United.[40] He scored his first goal with his new club the following 24 June, helping the hosts to defeat FC Cincinnati 3–0.[41]
^"V. Setúbal-Sporting, 2–1 (destaques)" [V. Setúbal-Sporting, 2–1 (highlights)] (in Portuguese). Mais Futebol. 4 November 2012. Archived from the original on 7 November 2017. Retrieved 6 November 2017.
^Fernandes, Nuno (26 January 2014). "Rio Ave vence na Covilhã e está nas meias-finais" [Rio Ave win in Covilhã and are in the semi-finals]. Diário de Notícias (in Portuguese). Archived from the original on 14 August 2023. Retrieved 9 March 2020.
^Vasconcelos, Ricardo (5 March 2016). "Pedro Santos cria um quarto dos golos" [Pedro Santos creates one quarter of the goals]. Record (in Portuguese). Archived from the original on 12 January 2023. Retrieved 12 January 2023.
^"#MLS | David Villa sigue implacable" [#MLS | David Villa remains relentless] (in Spanish). Deporte Total USA. 20 August 2017. Retrieved 15 January 2018.
^ ab"Pedro Santos – Leixões – Prémios foram entregues" [Pedro Santos – Leixões – Awards were handed out] (in Portuguese). Mitch Foot Futebol Matosinhos. 28 January 2012. Archived from the original on 15 November 2017. Retrieved 30 April 2017.