|Full name||Mikel Alonso Olano|
|Date of birth||16 May 1980|
|Place of birth||Tolosa, Spain|
|Height||1.80 m (5 ft 11 in)|
|1999–2002||Real Sociedad B|
|2003–2004||→ Numancia (loan)||10||(1)|
|2007–2008||→ Bolton Wanderers (loan)||7||(0)|
|* Senior club appearances and goals counted for the domestic league only.
† Appearances (Goals).
A product of Real Sociedad's youth ranks, as younger brother Xabi, Alonso was born in Tolosa, Gipuzkoa, and made his debut in La Liga on 22 April 2001 against Real Valladolid. However, the presence of his sibling and Mikel Aranburu in central midfield meant that he was restricted to a supporting role, and he was then sent on loan to second division's CD Numancia for the 2003–04 season but, while he was dedicated to the Soria team's bid for promotion, he remained keen to establish himself at Real Sociedad, returning at the end of the campaign; under the management of José Mari Bakero, the player's importance to the team was demonstrated in 2005–06, when he was the club's most used footballer playing in 37 games.
After brother Xabi had already settled in England with Liverpool (having arrived during the summer of 2004), Alonso also decided to move to the Premier League. He joined Bolton Wanderers, another team in north-west England, on a loan deal on 10 July 2007 with the option of a permanent deal at the end of the season. However, a change of club management meant he fell out of favour and, under new coach Gary Megson, he only made two first team appearances; at the end of the campaign Bolton opted not to make the loan deal a permanent one.
Alonso went back to Spain for the 2008–09 campaign but, upon his return to the Basque Country, discovered he was not a part of coach Juan Manuel Lillo's plans and was sent on trial to Olympiacos FC. This proved unsuccessful, however, and Real Sociedad exercised their right to buy the remainder of his contract, releasing him as a free agent.
Following his release from Real Sociedad, Swansea City boss Roberto Martínez offered countryman Alonso a chance to regain fitness. After his brother highly recommended both coach and the player to arrange the deal, he accepted the offer and joined the squad in training.
However, Alonso would not remain in Wales and, in late January 2009, moved to second level outfit CD Tenerife, after being contacted regarding a season-long contract. He accepted the offer and stated that he had "heard good things" about Tenerife. However, he remained a fan of his former club Real Sociedad, stating that, although the team were rivals to Tenerife, he hoped they gained promotion; he contributed with 11 matches as the Canary Islands side returned to the top flight after a seven-year absence.
In the 2009–10 campaign Alonso began as a starter, scoring with a rare header in the second matchday, a 1–0 home win against Athletic Bilbao. However, he appeared less regularly in the final stretch, as Tenerife were eventually relegated back.
In late June 2011, following another Tenerife relegation, 31-year-old Alonso returned to England, joining Football League One team Charlton Athletic. He made his official debut on 5 October in the Football League Trophy tie at The Valley against Brentford, conceding a penalty in an eventual 0–3 home loss.
The first son of Periko Alonso, who played with Real Sociedad and FC Barcelona, Alonso grew up surrounded by football: he and his younger brother, Xabi – who also appeared for Real Sociedad before representing with individual and team success Liverpool and Real Madrid – would go training with their father when he was playing for CE Sabadell FC; all three were midfielders.
- "Mikel Alonso: "A la Real y a mí nos interesa que juegue cada Domingo"" [Mikel Alonso: "Real and myself are interested in me playing every Sunday"] (in Spanish). Noticias. 16 January 2004. Retrieved 13 December 2008.
- "Alonso joins Bolton from Sociedad". BBC Sport. 10 July 2007. Retrieved 10 July 2007.
- "El club presentará mañana el ERE con Alonso y Stevanovic" [The club will release Alonso and Stefanovic tomorrow under ERE legislation] (in Spanish). El Mundo Deportivo. 3 September 2008. Retrieved 4 November 2008.
- Alonso enjoying his Swansea City stint; The Western Mail, 11 December 2008
- "Alonso: My brother Xabi told me to link up with Swans". Wales on Sunday. 14 December 2008. Retrieved 15 December 2008.
- El Tenerife confirma el fichaje de Mikel Alonso (Tenerife confirms Mikel Alonso's signing); Marca, 28 January 2009 (Spanish)
- Mikel Alonso: "Tenía varias opciones y Tenerife me pareció la más atractiva" (Mikel Alonso: "I had several options and Tenerife seemed the right choice"); Diario AS, 29 January 2009 (Spanish)
- "Athletic Bilbao lose 100% record". ESPN Soccernet. 23 September 2009. Retrieved 11 May 2011.
- "Mikel makes three". Charlton Athletic FC. 21 June 2011. Retrieved 22 June 2011.
- "Euell and Doherty head released list". Charlton Athletic FC. 10 May 2012. Retrieved 3 July 2012.
- Balague, Guillem (18 May 2008). "Dads and lads: Periko and Xabi Alonso". Liverpool FC. Retrieved 13 December 2008.