He came to Australia with his family (Father was a skilled migrant; fitter and turner) in 1970 and studied at a high school in the northern suburbs of Melbourne.

Prior to entering Parliament, Eren worked in a variety of fields with the most prominent being on the assembly line at Ford in Geelong.

After Eren's time at Ford he was an electorate officer for Kelvin Thomson the Federal Member for Wills for over five years.

In his first term in Parliament, John was a member of the Road Safety Committee and become the chair from 2007 to 2010.

In 2011 Eren was elevated as the parliamentary secretary to the Deputy Leader of the Opposition.