Mr. O'Brien is the last remaining classroom teacher of the original staff of MTHS from it's founding in what is now "Robert Lazar School" in 1968. Bob Lazar, a giant of education, set the tone of dedication and professionalism which he passed on to those for whom he was a leader, mentor and friend. Persons like, Robert Stafford, Robert Sueter and Mike O'Brien.

Mr O'Brien's continued guiding presence for the faculty over the years has earned him the moniker:"Father of Montville High School". In his 40 years of teaching at MTHS he has taught many courses and thousands of students.

His area of expertise has been in the Humanities and American History II, with particular concentration in biographies of political leaders. As a long time resident of Montville involved in civic affairs, he is the department resource on matters of local government and politics. Mr. O’Brien has traveled extensively throughout the United States and Canada. Throughout his career, he has coached innumerable basketball teams in Montville and neighboring communities. He is also a noted authority and lecturer in the field of antiques and decorative arts.