After graduating from the academy in 2007 he spent time on loan at Southend United and Swindon Town before returning to Reading and making his first team debut in 2009.

[7] The 2007 Peace Cup in South Korea saw Robson-Kanu involved with the Reading senior team for the first time with appearances against River Plate[8] and Shimizu S-Pulse.

[10] Not in contention for a regular place in the Reading first team, Robson-Kanu's first experience of senior football came on 30 January 2008 when he joined Southend United on loan until the end of the season.

[19] At the conclusion of his spell Swindon boss Danny Wilson hailed Robson-Kanu and fellow loanee Gordon Greer for their "fantastic impression" which helped the club pull away from relegation.

[26] Robson-Kanu finally made his competitive debut for Reading starting on the right wing in a 0–0 draw with Nottingham Forest on the opening day of the season.

[34] After the sale of Shane Long in August 2011, Robson-Kanu was played as a forward by Brian McDermott during some of the pre-season, a position he was familiar with from his Academy years.

He struck twice playing up front in the warm-up fixtures[35] and began the season in good goalscoring form with two in the first four games against Leicester City and Barnsley.

In Kébé, McAnuff and new signing Garath McCleary, Robson-Kanu faced stiff competition for places on the wing for Reading's return to the Premier League.

[42] The game against Villa proved to be Brian McDermott's last in charge and Robson-Kanu, having played only a bit-part role under the former manager, began to feature more prominently with the appointment of Nigel Adkins.

[43] He missed just two games under Adkins through a freak knee injury,[44] and with a regular berth on the wing finished the season strongly, scoring against Arsenal, and twice in Reading's 4–2 win over Fulham.

In a fans vote he finished in third place behind Adam Le Fondre and Alex McCarthy, despite all three players starting 13 or fewer league games all season.

[48] On 31 August 2016 after reportedly turning down "significant offers" from Asia, Robson-Kanu signed a two-year contract, with the option of a third year, with Premier League side West Bromwich Albion.

[53] After West Brom's relegation from the Premier League in 2018, Robson-Kanu scored twice and assisted once as his team beat Coventry City 5–2 to win the inaugural Regis Shield.

[57] On 19 October 2019, the day after signing a contract extension to keep him at the club until 2021, Robson-Kanu came off the bench to score a late winner in a 1–0 away win against Middlesbrough.

[61] On 27 May 2021 it was announced that Robson-Kanu would leave West Bromwich Albion after five years following the conclusion of his contract, having appeared for the club 154 times scoring 24 goals.

[66] The switch came about when Welsh coach Brian Flynn came to the Reading training ground to see Simon Church, and Glen Little jested that Robson-Kanu would be eligible for Wales through going on holiday there.

[74] Robson-Kanu played nine games in Wales' successful qualification campaign for UEFA Euro 2016, scoring on 13 October 2014 in their 2–1 home win over Cyprus.

[75] After being selected for the final tournament in France, on 11 June he came on as a 71st-minute substitute in place of Jonny Williams during their opener against Slovakia and scored the winner in a 2–1 victory in Bordeaux.

[76] He also started as striker in Wales' historic 3–1 quarter-final win on 1 July against Belgium in Lille and, after outwitting three defenders with a Cruyff turn, scored the team's second goal.