Williams took to social media to celebrate his graduation from Otago Polytechnic where he earned a Bachelor of Applied Management (Sport Management) with distinction.
The 33-year-old posted a picture of his new degree alongside another of him in his graduation gown surrounded by his family.
"Yes a Pacific Islander, boxer, league, sevens & rugby player can GRADUATE!" he said in the post.
"Don't ever let anyone pigeon hole you. Alhamdulillah."
Williams enrolled in Otago Polytechnic last year through Capable New Zealand - a programme run by Otago Polytechnic that allows students to study remotely and also use their Auckland campus.
The All Blacks midfielder was able to dedicate more of his time to studies recently due to a string of injuries which have kept him on the sideline for the Blues.