Starting out with the likes of NBT FC and AM Gunners of the Brunei Premier League, Najib's performances at the 2012 Hassanal Bolkiah Trophy as team captain prompted a move from MS PDB to Brunei's only professional club, DPMM [REF].
After appearing only seven times in the 2015 season, his club head coach Steve Kean advised him to switch to the left-back position for him to gain playing time (as he has done to Helmi Zambin and Aminuddin Zakwan Tahir).