[3][4] After graduating high school, he continued his studies at Pasadena City College and the University of Southern California.
Jack Hadjinian was a crew member of the 1997 APBA World Championship Offshore Race Team X-Plosive.
[6] The swearing-in ceremony was attended by Sheriff Jim McDonnell, Los Angeles City Councilman Paul Krekorian, and Archbishop Moushegh Mardirossian, Prelate of the Armenian Apostolic Church of America.
[6][7] Jack Hadjinian once again ran for reelection in November 2020, but he finished in third place, with less than 14 percent of the vote, divided among five candidates (the top-two vote-getters would be elected).
[9] Hadjinian currently serves on the Executive Council of the Western Prelacy of the Armenian Apostolic Church of America and the County of Los Angeles Commission on Alcohol and Other Drugs.