O'Brien is a lifelong resident of the Mahoning Valley and graduate from John F. Kennedy High School as well as Youngstown State University.
[1][self-published source] O'Brien announced in early 2014 that he would seek a seat in the Ohio House of Representatives to replace Tom Letson who was term-limited.
[3] He faced former Republican state Representative Randy Law in the general election, in what became a very tight race.
In 2005, Mayor Michael J. O'Brien was fined by the Ohio Ethics Committee for mishandling campaign contributions.
"According to a complaint filed in July by Victor V. Vigluicci, special prosecutor in Trumbull County, O'Brien from 2000 to 2003 received $2,035 in campaign contributions that were deposited into the joint personal checking account with his wife, or the personal savings of son Dominic and Louise O'Brien.