His youth career began with the Hertfordshire-based professional football club ‘Watford’ in 2000.
In 2001, Akinfenwa joined the Lithuanian football team ‘FK Atlantas’ on the advice of his agent. This marked the beginning of his senior career. He was on the ‘FK Atlantas’ roster during the ‘Lithuanian Football Cup’ of 2000–2001 and led the team to win the Lithuanian annual football tournament by delivering the only goal against ‘FK Žalgiris’ in the final match held on May 19, 2001, at the ‘Aukštaitija Stadium’ in Panevezys. Akinfenwa, however, faced racial abuse from fans in the country and described the experience as “just brazen.”
In early 2003, he returned to the UK and joined the ‘Barry Town United Football Club.’ He helped the club win the ‘Welsh Cup’ and the ‘Welsh Premier League.’ He had a rather short stint with the club, which was facing a financial crisis at that time, resulting in it releasing its professional playing staff.
In October 2003, he joined ‘Boston United’. He netted a last-minute goal in his debut match with the club. This resulted in a 2–1 win by the club in the ‘Football League Trophy’ match against ‘Swindon Town.’
He had brief stints with ‘Leyton Orient FC’ and ‘Rushden & Diamonds FC’ before he joined the ‘Doncaster Rovers’ in February 2004. In July that year, he signed with ‘Torquay United’ as a replacement for Scottish footballer David Graham. He netted a total of 16 goals for the club during the 2004–2005 season and became the ‘Torquay United Player of the Year’ in 2005.
He joined ‘Swansea City’ in July 2005. The club was instructed to pay £85,000 as compensation. His debut match for the club took place at its home stadium, the ‘Liberty Stadium,’ located in the Landore area of Swansea. The match saw him net a goal against the ‘Tranmere Rovers.’ This marked the first competitive goal scored at the stadium.
The 2006 ‘Football League Trophy’ final, played between ‘Swansea City’ and ‘Carlisle United,’ on April 2 that year, at the ‘Millennium Stadium,’ Cardiff, Wales, saw ‘Swansea City’ win 2–1. The winning goal was scored by Akinfenwa. During his first season with the club, Akinfenwa also helped ‘Swansea’ reach the ‘League One’ promotion play-off final. The following season, he played regularly until he suffered from a broken right leg. Akinfenwa refused to sign a new contract with the club after the end of the second season.
Although he gave his consent to sign with the professional football club ‘Swindon Town’ on June 29, 2007, he could not clear the medical test. Following this, in November 2007, he agreed to play on a month-to-month contract with the ‘Millwall Football Club.’
He signed with ‘Northampton Town’ on January 18, 2008, for the rest of the 2007–2008 season and scored a total of 7 goals that season. After the end of the season, he signed a fresh year-long contract with the club on May 30, 2008. He scored 15 goals during the 2008–2009 season and 17 goals during the 2009–2010 season, ending his tenure with the club in May 2010. In 2010, he became the ‘Northampton Town Player of the Year.’
He signed a year’s contract with ‘Gillingham FC’ on July 29, 2010. He scored 11 goals for the club during the 2010–2011 season and formed a strong partnership with striker Cody McDonald.
On May 25, 2011, he returned to ‘Northampton Town.’ His career’s first and only hat-trick to date was for the club in a match against ‘Accrington Stanley’ on November 10, 2012. He auctioned the shirt he had worn in this match 3 years later, when the club faced a financial crisis. The proceeds of this auction, amounting to £440, were donated to a supporters' trust. He was released by the club at the end of the 2012–2013 season.
On July 2, 2013, he re-signed with ‘Gillingham.’ He scored 10 goals for the club during the 2013–2014 season, apart from building another partnership with McDonald. Following the end of the 1-year contract, Akinfenwa left ‘Gillingham.’
He signed with ‘AFC Wimbledon’ on June 20, 2014, and scored 15 goals during the 2014–2015 season. He had a contract extension with the club on June 8, 2015, and was released from the contract on May 30, 2016, after he scored a penalty against ‘Plymouth Argyle’ in the ‘League Two’ play-off final. ‘AFC Wimbledon’ sealed a 2–0 win in the match. He scored 8 goals for the club in the 2015–2016 season and became the ‘AFC Wimbledon Player of the Year’ in 2015.
Akinfenwa then signed a year-long contract with the ‘Wycombe Wanderers.’ He currently plays with them as a striker. He scored 18 goals in each of the 2016–2017 and the 2017–2018 seasons for the club and became part of the ‘PFA Team of the Year: 2017–18 League Two.’ He was also named the ‘Wycombe Wanderers Player of the Year’ in 2017.
Akinfenwa runs the clothing label ‘Beast Mode On.’ He weighs about 16 stone (101 kg) and can bench press 200 kg, nearly double the weight of his own body. Various editions of the ‘FIFA’ videogame series rank him as the world’s strongest player. In September 2014, he received an invitation to attend the launch party of the football simulation video game ‘FIFA 15,’ a game developed by ‘EA Canada’ and published by ‘Electronic Arts.’