He began his career at Arsenal, where he won a FA Youth Cup and two Premier Academy League titles. He also played for English sides Wolverhampton Wanderers, Charlton Athletic and Fulham. In January 2014, Frimpong moved to Barnsley, then to Russian team Ufa in September of that year. He then featured for Arsenal Tula and subsequently that of AFC Eskilstuna of the Swedish Allsvenskan.
Although Frimpong represented England at youth level, in March 2013 he made his full international debut for Ghana, his country of birth. He holds both a Ghanaian and a British passport.
Frimpong was born in Kumasi, Ghana, but moved to Tottenham at a young age where he was originally discovered by Arsenal and enrolled at the Hale End Academy at the age of nine alongside fellow graduate Jack Wilshere. He attended Gladesmore Community School in Tottenham until he was 14, when he left to focus on playing football full-time at Arsenal's youth academy.
Frimpong signed for Arsenal aged nine. He began his Arsenal career in their youth academy, scoring against Coventry City and Milton Keynes Dons, amongst others. Arsenal added him to their reserve team in 2008, whereupon he made his debut for the reserves on 5 October 2009 against Chelsea. Frimpong as well as fellow academy member Jay Emmanuel-Thomas were on the bench for the match against Sheffield United.
On 22 May 2009, Frimpong was injured on the quarter-hour mark of the FA Youth Cup Final against Liverpool and was substituted. He went on to win a league and cup double as Arsenal went on to win the Youth Cup together with that of the Premier Academy League of 2009. Frimpong again won the League with Arsenal in the following year being 2010.
He featured heavily in Arsenal's pre-season in Austria and received praise from senior manager Arsène Wenger for his performances at the 2010 Emirates Cup: "I believe Frimpong has done really well as well. He is a bit less of a dribbler but he is a fighter and he is a winner."
On 19 August 2010, Frimpong injured an anterior cruciate ligament (ACL) in training and was out injured for nine months. After returning from the injury, on 17 June 2011, Frimpong claimed he was in talks with Championship club Cardiff City and League One side Charlton Athletic over a possible loan deal, which could provide him with regular football.
Frimpong made his Premier League debut for Arsenal in their match against Newcastle United on 13 August 2011, coming on as a second-half substitute for Tomáš Rosický. On 16 August 2011, Frimpong came on as a second-half substitute for Rosický again, this time in the UEFA Champions League match against Udinese. He made his first start in the Premier League on 20 August 2011 against Liverpool, but ended up being sent off in the 69th minute of the match after receiving a second yellow card for a challenge on Lucas. Following Arsenal's loss to Manchester City in the League Cup quarter-finals, Frimpong and then-teammate Samir Nasri clashed in the tunnel. They had tussled throughout the tie and at the end of the match they appeared to start arguing as the teams walked off the pitch, before continuing their disagreement in the tunnel. Following the incident, Nasri and Frimpong were not disciplined over the incident.
Loan spell at Wolves
On 1 January 2012, it was confirmed that Frimpong had joined fellow Premier League side Wolverhampton Wanderers on loan until the end of the season. The following day, he made his debut, starting in a 2–1 loss to Chelsea. In only his fifth appearance for the club, however, he ruptured a cruciate ligament in his right knee during a 2–1 win at Queens Park Rangers, effectively ending his season. He was then returned from his loan early to Arsenal, as his injury would rule him out for the rest of his time at Wolves.
On 19 November 2012, Frimpong joined Championship side Charlton Athletic on a six-week loan deal until 1 January 2013 and a few weeks later, on 25 January 2013, joined Fulham on a season-long loan deal.
Frimpong joined Barnsley for an undisclosed fee on 31 January 2014. He went straight into the squad for the Yorkshire derby against Sheffield Wednesday, but was sent off after 31 minutes. Following Barnsley's relegation from the Championship, Frimpong was released after only four months at the club.
On 1 September 2014, Frimpong signed a three-year contract with Russian Premier League side FC Ufa. In the first game of the 2015–16 Russian Premier League, a match against Spartak Moscow, Frimpong was sent off in the 31st minute for making an obscene gesture at a Spartak supporter. Afterwards, Frimpong took to social media to apologize for his action, but at the same time blamed racist abuse from the fans for what provoked him to make that gesture. Frimpong later received a two-match ban for the incident, a punishment he called "a joke." He was released from his Ufa contract on 4 April 2016 by mutual consent.
On 8 August 2016, Frimpong signed two-year contract with Arsenal Tula.
On 21 February 2017, Frimpong signed a two-year contract with Swedish Allsvenskan side AFC Eskilstuna.
On 17 August 2017, Frimpong signed a two-year contract in Cyprus with Ermis Aradippou.
Frimpong played six matches with England's under-16 team in 2007. In March 2008, Frimpong scored a 71st-minute goal for England against Germany's under-16 team in the Montaigu Tournament to give England a 1–0 win.
In 2009, Frimpong said, "No matter what, I will always play for Ghana because at the end of the day, from what I believe, I am a Ghanaian." In August 2010, Frimpong was called up for the England under-19 squad to face Slovakia the following month, though he was later forced to withdraw from the squad after suffering his ACL injury.
In February 2011, Frimpong said, "I have always told my family that if Ghana calls me, I will personally ride my own bicycle from England to Ghana [to play for the Black Stars]." In August, Frimpong had planned to spectate at a friendly match between Ghana and Nigeria at Vicarage Road in Watford, but the game was postponed due to the 2011 England riots. Later that month, Frimpong received his first call-up for the England under-21 team.
On 6 September 2011, it was announced by the Ghana Football Association (GFA) that Frimpong has pledged his future to Ghana. FIFA cleared him to play for Ghana in November 2012. He made his Ghana international debut on 24 March 2013 during a 2014 World Cup qualifying match against Sudan.
Frimpong is known for his energy in the midfield and has been compared with ex-Arsenal player Alex Song and various other African midfielders who have lots of pace and stamina. He has also been called a younger version of Michael Essien because of his hard work in the defensive midfielder role.
Frimpong is the cousin of Norwegian-Ghanaian professional footballer Yaw Amankwah, who plays as a centre back for Danish club Hobro. He is also a cousin to Lethal Bizzle. In 2012, Frimpong contributed a rap verse to the remix of Bizzle's track "Leave It Yeah."As of match played 23 July 2017
FA Premier Academy League: 2008–09, 2009–10
FA Youth Cup: 2008–09
Montaigu Tournament: 2008