Former Fulham Under-16 defender Magnus Okuonghae played for Norwich's Under-19s in their defeat at West Ham on 2nd March 2002. He was later on the bench for Leicester's Under-19s in their 3-1 defeat to Norwich on 12th April 2002

Magnus then joined Rushden & Diamonds, playing for their youth team although he was called up to the bench for their clash with Cambridge United in January 2003.

Following Rushden's relegation to the Conference at the end of 2005/6 season, Magnus rejected the offer of a new contract and left the club. After a trial with Gillingham, he joined Aldershot in the middle of August 2006. Days after he was called up to the England semi-professional side, he switched to St Albans City at the end of August 2006 on a non-contract basis. He added a third Conference club in the season in January 2007 when he joined Crawley Town. He had made twenty appearances for St Albans.

Maguns was capped by the England National Game XI before joining Dagenham & Redbridge on 1st June 2007. In February 2009, he was loaned to Weymouth.

On 1st July 2009, Okuonghae left Dagenham & Redbridge and signed a 2 year contract with Colchester United.

Sky Sports speculated in January 2012 that Norwich, Charlton, Burnley, Crystal Palace and Millwall are all keen on Magnus who had become a regular in the Colchester defence

He made over 200 appearances in a six-year spell for Colchester but an Achilles injury ruled him out of much of the 2014/15 campaign. Released at the end of the season, he joined Luton on a two year contract on 1st July 2015.

He was released by Luton on 31st August 2016, having made 14 appearances. During his time at Luton, he was loaned to Hartlepool (4 appearances). On 25th November 2016, he signed a short term contract until January 2017 with Dagenham & Redbridge, making four appearances. He then signed for Maidstone on 20th February 2017, making five appearances that season. The following season saw him spent some time on loan at Welling United (10 appearances).

Released by Maidstone at the end of the 2017/18 season, having made a total of 33 appearances, he joined Dulwich Hamlet (National League South) on 23rd July 2018.