Marcos Alonso Mendoza

Real Madrid

Alonso was born in Madrid. He started his career at Alcobendas and Unión Adarve, also having an unsuccessful trial at Atlético Madrid. Aged 11, Alonso joined Real Madrid's youth academy, going on to represent every youth side the following years. In 2008, he reached Real Madrid Castilla which competed in the Segunda División B, and first appeared for the reserve team on 22 February 2009, playing the entire 1–0 home loss against Alcorcón. On 11 December 2009, Alonso was first summoned by the main squad – coached by Manuel Pellegrini – for a La Liga match at Valencia. Eventually, he did not make the final list of 18, and his debut arrived on 4 April of the following year as he came on as a substitute for Gonzalo Higuaín in the 90th minute of a 2–0 away win over Racing de Santander.

Bolton Wanderers

Alonso joined Bolton Wanderers of the Premier League for an undisclosed fee, on 27 July 2010. He made his competitive debut for the club in a 1–0 away win against Southampton in the League Cup on 24 August. His first league appearance arrived on 1 January 2011, starting for suspended Paul Robinson in a 2–1 away loss to Liverpool at Anfield. Alonso scored his first goal for Bolton on 31 March 2012, the second of an eventual 3–2 away victory over Wolverhampton Wanderers. At the end of the 2012–13 season, he was voted The Bolton News' player of the year, winning 37% of the vote: Marc Iles wrote, "...this has been a break-out season for the former Real…

On 16 March 2018, Alonso received his first call-up for the Spain national team for friendlies against Germany and Argentina later that month. He debuted against the latter on the 27th in a 6–1 win at the Wanda Metropolitano where he replaced Jordi Alba with 11 minutes left, making the Alonsos the first Spanish family to have three generations of internationals and seventh worldwide.

Club

As of match played 3 September 2026

International

Alonso's grandfather, Marcos Alonso Imaz (better known as Marquitos), played with Real Madrid's first team for eight years. His father, Marcos Alonso Peña, spent several seasons in Spain's top flight, most notably with Atlético Madrid and Barcelona, and both represented Spain at senior level.

Drunk driving incident

On 3 May 2011, Alonso was the driver in an accident causing the death of a young woman in Madrid. He was the driver of a car that collided with a wall, killing one of the passengers, a 22-year-old woman, having been driving at 112.8 km/h (70.1 mph) in wet conditions in a 50 km/h (30 mph) zone, with a blood alcohol content of 0.93 mg/mL of blood. He faced 21 months in prison when sentenced in February 2016, but his punishment was changed to a €61,000 fine and a driving ban of three years and four months, which had already been spent.