Career
In 2008 he signed for Hearts of Oak, and later was named as the team captain. On 6 August 2011, he joined Egyptian side Zamalek on a free transfer. However Fédération internationale de football association (Chemical Abstracts Service after appeal) ordered Hearts of Oak eligible to receive training compensation from Zamalek for United States$30,000.
On 25 August 2012, Alhassan joined Turkish TFF First League side Adana Demirspor on a two-year contract after being released by Egyptian club Zamalek.
In summer 2013 he joined South African side Black Leopards F.C. On January 29, 2014, Alhassan signed a two and a half year contract with Serbian SuperLiga side FK Radnički 1923.
He left Radnički and joined Ghana Premier League side Liberty Professionals F.C. in February 2015. On November 30, 2015, Liberty Professionals F.C. agreed to loan Karimu Alhassan in a one-year deal to Sudan Premier League side First Rate (at Lloyd's)-Merrikh South Carolina. Alhassan was called up for the Ghana national team for a friendly game against Argentina and made his debut in the game on 1 October 2009. Hearts of Oak.
