Christian was a Feyenoord Ghana graduate. Started at FC Porto and went to Chelsea in 2013. With Porto he became Champions twice and also won the Supercup in 2013. At Chelsea he was loaned out to Vitesse, Everton, Bournemouth and FC Malaga. In 2017 he was sold to Newcastle United and they got promoted that same season. He played at the World Cup in 2014 and went to the Africa Cup 4 times with 3 goals. He died in February 2023 during an earthquake in Turkey. At that time he was a player of Hatayspor.