In his career, O'Shea worked as a social worker, and later became the director of a community center.[1] He also served as an aide to his 19th ward aldermanic predecessor Virginia Rugai.[1]
Among the committees O'Shea has served on are Aviation,[6] Budget and Government Operations,[1][6] Committees and Rules,[6] Economic, Capital and Technology Development,[6] Education and Child Development,[1][6] Finance,[6] Health and Human Relations,[6] License and Consumer Protection,[1] Health and Human Relations,[6] Public Safety,[1] Transportation and Public Way[1] and the joint committees on Committees and Rules/Finance,[6] Health and Human Relations/Workforce Development,[6] Public Safety/ Education,[6] as well as the Special Legislative Committee on the Census.[6] In June 2018, mayor Rahm Emanuel appointed O'Shea as the chairman of city aviation committee.[7] He also has served as the vice chair of the Committee on Committees and Rules and the Joint Committee on Committees and Rules/ Finance.[6]
Participatory budgeting is a Chicago democratic process in which community members directly decide how to allocate part of a public budget. The 19th Ward does not participate in participatory budgeting with O'Shea opting to keep the menu budgeting decisions to his office.
In the 2019 Chicago mayoral election, O'Shea endorsed Jerry Joyce in the first round of the election[8] and endorsed Lori Lightfoot in the runoff.[9] His endorsement of Lightfoot has been credited with securing her strong support in his ward in the runoff vote.[10]
