After starting out at Racing de Santander and appearing for the club in La Liga, he went on to spend the better part of his career with Porto, playing 254 competitive matches and winning the 2017–18, 2019–20 and 2021–22 Primeira Liga championships. He also had spells abroad in Greece (Olympiacos, twice), Russia and Italy.
Santander-born Marcano, a youth graduate of hometown's Racing de Santander, made his first appearance with the main squad in an away win over UD Almería on 30 September 2007, due to injuries in the Cantabrian side.[3] However, he had to leave the pitch in the second half of the game, also due to injury, and was unable to play for three months.[4]
Marcano signed a six-year deal with Villarreal CF in early July 2009.[8] He was first-choice for most of the first part of his first season; however, after consecutive poor performances, he fell out of favour, even losing his position in the defensive pecking order to 19-year-old Argentine Mateo Musacchio (originally signed for the B side).[9] His one goal was on 4 May 2010 in a 4–2 loss at UD Almería.[10]
Deemed surplus to requirements at Villarreal for 2010–11, Marcano was loaned to Getafe CF on 8 June 2010.[11] Benefitting from injuries to both Mario and Rafa, he was regularly used in both defensive positions as the Madrid outskirts team narrowly avoided relegation; he netted his only goal of the season on 24 October 2010, in a 3–0 home win over Sporting de Gijón.[12] The following 20 February on Racing's visit to the Coliseum Alfonso Pérez, he was sent off for a foul on Giovani dos Santos from which Pablo Pinillos scored the only goal from the penalty spot with three minutes remaining.[13]
In the 2014 winter transfer window, Marcano returned to his previous club on loan until June and with the option to subsequently make the deal permanent.[18]
Porto
Marcano signed a four-year contract with FC Porto on 11 August 2014, replacing Manchester City-bound Eliaquim Mangala. He became the sixth Spaniard to join the Portuguese club after compatriot Julen Lopetegui took over three months earlier.[19]
On 6 November 2016, after several occasions on which he wore the armband after the titular was replaced, Marcano acted as captain for the first time as a starter, in a 1–1 home draw against S.L. Benfica.[22] He scored his first Champions League goal on 17 October 2017, closing the 3–2 group-stage away defeat to RB Leipzig just before half-time.[23][24] In addition, he netted a career-best five times in the domestic league in the 2017–18 campaign, which ended with the conquest of the Primeira Liga championship after five years.[25]
Roma
Marcano moved to the Italian Serie A on 31 May 2018, with the 30-year-old agreeing to a three-year deal at AS Roma.[26] He made his league debut on 31 August, playing the first half of the 2–1 away loss to AC Milan.[27]
Marcano returned to former club Porto on 11 July 2019, again being given the number 5 jersey and signing a four-year contract.[31] He contributed five goals in the first season in his second spell, winning another domestic league.[32]
On 26 April 2023, Marcano's 16th-minute header opened an eventual 2–1 victory at F.C. Famalicão in the first leg of the semi-finals of the Taça de Portugal; in the process, he became Porto's all-time scorer from a defensive position at 27 goals.[38] On 15 September, he suffered another ACL injury in the first half of the league fixture against C.F. Estrela da Amadora and was sidelined for several months.[39]
^Chimeno, Jesús (28 October 2008). "Doctor Jekyll y mister Hyde" [Doctor Jekyll and Mister Hyde]. Diario de Cantabria (in Spanish). Archived from the original on 1 October 2008. Retrieved 29 October 2008.
^Fernández, V. (11 February 2009). "Marcano, el joven zurdo que Monchi ya espía" [Marcano, the young lefty Monchi is already eyeing]. Diario AS (in Spanish). Retrieved 2 November 2022.
^Fernández-Cueto, F. (17 April 2009). "Muñiz piensa en Marcano como central" [Muñiz thinking of Marcano as stopper]. El Diario Montañés (in Spanish). Retrieved 2 November 2022.
^Fabián, R. (12 May 2010). "El Villarreal quiere vender a Marcano" [Villarreal want to sell Marcano]. El Periódico Mediterráneo (in Spanish). Retrieved 19 April 2018.