[10] When Valencia was aged 11, scout Pedro Perlaza spotted him playing on a dusty field near his home, and signed him to the local FA-run sports academy in Sucumbíos.

[9] At the age of 16, Valencia did not tell his father he left home to take up an offer to play for El Nacional, the military-backed club in Quito.

[11] Nobody knew about Valencia's decision, except his mother and his elder brother, Carlos Alfredo, who paid the fare for his eight-hour bus journey.

[11] Valencia started his career at El Nacional and within a year he was fast-tracked into the under-20s, where he played alongside striker Christian "Chucho"’ Benítez.

[citation needed][15] On 3 August 2006, Valencia joined English Premier League club Wigan Athletic, initially on a year-long loan deal.

[19] Valencia was sent off for the first time for Wigan on 9 April 2007, receiving a straight red card for a two-footed challenge on Wilfred Bouma during a 1–1 away draw against Aston Villa.

[22] Valencia scored his first goal of the 2007–08 season in a 2–0 win over Derby County on 23 February 2008,[23] before netting his first Wigan brace in a 2–0 away victory over Aston Villa on 3 May 2008.

[25] He then grabbed a goal in the 2–1 home win over Manchester City on 28 September 2008,[26] but followed it up by receiving a red card in the 3–2 loss at Liverpool on 18 October 2008.

[36] Valencia provided the assist for Wayne Rooney's winning goal in the 2010 League Cup Final against Aston Villa on 28 February 2010 and was named player of the match as United won 2–1.

[37] On 25 April 2010, Valencia was included in the PFA Premier League Team of the Year in his debut season for the club alongside teammates Patrice Evra, Darren Fletcher, and Wayne Rooney.

Days later, he scored the first goal in United's 4–1 victory against the German team Schalke 04 in the second leg of the semi-final of the 2010–11 UEFA Champions League, game in which he was selected as player of the match.

[43] Prior to the start of the 2011–12 season, Valencia picked up an ankle injury on international duty with Ecuador at the Copa América during the summer.

Valencia scored his first goal of the season, in a fourth round League Cup tie against Aldershot Town, receiving the ball in the middle of the park and then turning and firing in from 25-yards to seal a 3–0 victory.

On 2 April 2012, in his 100th appearance for the club in all competitions,[44] Valencia scored the first goal in a 2–0 win against Blackburn Rovers, powerfully curling the ball around Paul Robinson and inside the far corner.

On 22 April 2013, Valencia won his second Premier League title after Manchester United defeated Aston Villa in a 3–0 home win.

Valencia started the Champions League campaign with a goal against Bayer Leverkusen the fourth in a 4–2 home victory as well as giving Robin van Persie an assist for the first on that night on 18 September 2013.

[51] The arrival of new manager Louis van Gaal led to Valencia being deployed in both the right-back and right-wing back positions, where he had occasionally played under both Sir Alex Ferguson and David Moyes.

[56] Valencia played the full 120 minutes at right-back in the 2016 FA Cup Final against Crystal Palace on 21 May 2016, in which United won 2–1 after extra-time.

[58] On 19 March 2017, Valencia made his 200th league appearance for United and scored in injury time, after goalkeeper Víctor Valdés slipped, to complete a 3–1 victory over Middlesbrough.

[62] After being ruled out for four weeks with a hamstring injury, Valencia returned to action as he scored the opening goal in a 3–0 home victory against Stoke City in January 2018.

[63] At the beginning of the 2018–19 season, and after the retirement of Michael Carrick, Manchester United manager José Mourinho announced Valencia would be the club's first captain.

[65] Valencia left Manchester United having registered 325 Premier League appearances, which remains a record for a South American player.

On 27 June 2007, Valencia netted Ecuador's first goal of their 2007 Copa América campaign, however they eventually lost the match 3–2 to Chile and finished the tournament bottom of their group.

[84][85] Valencia captained La Tri during all three of their matches at the World Cup and was sent off for a foul on Lucas Digne during their final game against France, a goalless draw at the Maracanã which saw his team eliminated.

[citation needed] Along with former Wigan Athletic teammates Maynor Figueroa and Wilson Palacios, Valencia began taking English lessons.

[92] Valencia also has a tattoo on his upper arm paying tribute to former international teammate and close friend Christian "Chucho" Benítez, who passed away in 2013.