Essien started his career playing for Liberty Professionals in Ghana. In 2000, he moved to France to join Bastia, where he would spend three seasons and appear in over 60 matches before joining Ligue 1 title holders Lyon in 2003.
At Lyon, Essien won back-to-back league titles in 2003–04 and 2004–05, and won Ligue 1 Player of the Year in 2005. During his five-year stint in France, he acquired French citizenship.
In 2005, Essien signed with Premier League side Chelsea for a £24.4 million transfer fee and, at the time of his signing, was the most expensive African footballer in history. At Chelsea, Essien helped the club win the Premier League in 2006 and 2010, as well as three FA Cups and one League Cup.
He won the UEFA Champions League in 2012, while also placing as runner up in the 2008 UEFA Champions League. He has won the Chelsea Goal of the Season award twice, in the 2006–07 and 2008–09 seasons.
Essien's international career started with the Ghana under-17 national team, the Black Starlets when he played in the 1999 FIFA U-17 World Championship in New Zealand and won the bronze medal. In 2001, despite being one of the youngest players in the tournament, Essien participated in the 2001 FIFA World Youth Championship with the Black Satellites in Argentina, where the nation finished runners-up to Argentina.
Essien made his competitive senior debut in the 2002 Africa Cup of Nations against Morocco on 21 January 2002 but had played for Ghana in a pre-tournament friendly against Egypt on 4 January 2002.
On 16 May 2006, Essien was selected to be part of the team that represented Ghana at the 2006 FIFA World Cup in Germany.
In the 2008 Africa Cup of Nations, Essien turned in another strong performance, driving the team to the semi-finals with his power-packed performances. He was voted as an All-Star Player during the tournament.
Having announced that he will be standing down from the national team to focus on his Chelsea future, Essien returned to Ghana's squad in August 2013 for the team's final 2014 World Cup qualifiers. He appeared as a second-half substitute in a 2–1 defeat of Zambia as the Black Stars secured qualification to the final round.
He started in both play-off matches against Egypt and was named in Ghana's squad for the tournament finals. He made one appearance, coming on as a second-half substitute in the opening 2–1 defeat to the United States.
In July 2018, Essien has announced his retirement from international football, after over 12 years of active service with Ghana. He said that he even retired before the 2014 World Cup but he was called back by the current Ghana coach, James Kwesi Appiah to come and help the team.
He has been capped 58 times and scored 9 goals for the Ghana national team.