Anichebe was born in Lagos, Lagos State, Nigeria but moved to Liverpool aged one, his family originally living in Toxteth before settling in Crosby. He is a cousin of former professional football player Iffy Onuora, Olympian Anyika Onuora and professional basketball player Chiz Onuora. He is also an Olympic silver medallist, competing for Nigeria in the 2008 Olympics.
Anichebe made his reserve team debut as a 15-year-old and his first team debut less than two years later on 27 February 2006, as a substitute in the 89th minute of Everton's FA Cup 4th round tie against Chelsea, replacing Simon Davies. He signed his first professional contract with Everton, a two-year deal, in April 2006. On 7 May 2006, he scored his first Premier League goal against West Bromwich Albion. He was awarded Everton's Reserve Player of the Season for the 2005–06 season.
Anichebe scored his first two Premier League goals of the 2006–07 campaign in a 3–0 win against Newcastle United on 30 December 2006. His contract was extended by four years towards the end of the season as Everton qualified for the UEFA Cup. In the UEFA Cup Anichebe scored four times, against Metalist Kharkiv, Larissa, FC Nuremberg and SK Brann of Norway after coming on as a late second-half substitute in many of the games. At the end of the season he was voted by Everton fans as their Young Player of the Season.
On 22 February 2009, in a game against Newcastle United, a tackle from Kevin Nolan left Anichebe and unable to play for 11 months. Nolan, who received a straight red card for the foul, later settled out of court when Anichebe sued for loss of earnings. He returned to first team action in January 2010, in a 2–0 victory over Sunderland. His first goal on rejoining the squad came two months later in a 2–2 draw with Birmingham City. In January 2011, he signed a new four-and-a-half-year contract with Everton along with teammate Seamus Coleman.
Anichebe suffered a groin injury while on international duty in September and did not play for the rest of 2011. He made his return as a second-half substitute on 1 January 2012, against West Bromwich Albion and scored in the 87th minute to give Everton a 1–0 away win. He continued his comeback by coming off the bench to score the equaliser in a 1–1 with Aston Villa on 14 January. Anichebe continued his goalscoring form by scoring his 3rd goal of the season as a substitute in a 1–1 with Wigan Athletic on 4 February. His appearance also meant he became Everton's most used substitute in the history of the club, breaking Duncan Ferguson's old record of 82.
In his first Premier League start of the 2012–13 season, Anichebe scored the opening goal in a 3–0 win over Swansea with a left footed effort from close in. He then missed a number of games due to an hamstring injury, but returned in December to score a header to level the game against West Ham United at 1–1. Everton went on to win 2–1. He provided two assists during the festive season before scoring the winner against Newcastle on 2 January 2013.
In February, Anichebe scored his first goal in the FA Cup of his Everton career against Oldham Athletic in a match which ended 2–2. In the second half of the season he was used as Everton's main striker due to his impressive displays and the drop in form of Nikica Jelavić. In late March Anichebe stated that he wanted to finish the season with a goal tally in double figures, but he finished with eight goals from 32 games, which is still the most he has scored in a single season in his career.
On 2 September 2013, Anichebe moved to West Bromwich Albion in a deal which could rise to £6 million. On 2 February Anichebe scored his second league goal against Liverpool to earn West Brom a point. On 11 February he came on as a substitute and scored against Chelsea to earn West Brom a point.
On 18 May 2016, it was announced that Anichebe and teammate Stéphane Sessègnon would leave the club.
On 2 September 2016, Anichebe signed a one-year deal with Sunderland, to play under manager David Moyes. He was the club's ninth signing of the summer. His first goal for the club came on 5 November 2016, when he scored in a 2-1 win against Bournemouth, as Sunderland came from behind, with 10 men, to secure their first win of the season. He followed that up in the next match, on 19 November 2016, when he scored two goals in a 3-0 home win against Hull City. His performances in November earned him a nomination for the PFA Fans Player of the Month award.
On 23 June 2017, Anichebe joined Chinese club Beijing Enterprises.
Anichebe made his debut for Nigeria on 26 March 2008 in an Olympic games qualifying match against South Africa. Anichebe came off the bench to score the final goal in a 3–0 victory for Nigeria. He made his first start for Nigeria alongside fellow Everton player Yakubu in a friendly against Austria on 27 May 2008 being replaced at half time.
He was selected to represent Nigeria at the 2008 Beijing Olympic Games and on 10 August 2008 he scored Nigeria's second goal in their match against Japan. Nigeria eventually reached the final, which they lost 1–0 to Argentina, with Anichebe receiving a silver medal.
He was not selected on the final 23-man roster for the 2010 World Cup in South Africa despite a good performance during a friendly against Saudi Arabia. He scored his first senior team goal in the March 2011 friendly against Kenya. Anichebe suffered a groin injury during a 2012 African Cup of Nations qualifying match against Madagascar in September 2011, with Nigeria's coach Samson Siasia blaming the poor pitch. The Super Eagles won the match 2–0, but would miss out on qualification for the tournament a month later, with the injured Anichebe unable to take part in the deciding group game against Guinea.
In October 2012, Anichebe announced he was focusing on his form for club side Everton, rather than on earning a return to the Nigerian team. He was subsequently left out of the squad for the 2013 Africa Cup of Nations, a tournament which Nigeria won. In May 2013, Anichebe temporarily retired from international football to concentrate on his club career. However, he stated that he will return to international football in the future.As of match played 06 February 2017.
Scores and results list Nigeria's goal tally first.