She was the first female commissioner of the Boston Police Department, when appointed by Mayor of Boston Thomas M.
Menino in February 2004.
On May 9, 2006, her 52nd birthday, O'Toole officially announced that she was leaving the Boston Police Department to move to Ireland.
She was the first Chief Inspector of the Garda Inspectorate, set up to ensure that the resources available to the Garda SÃochána are used so as to achieve and maintain the highest levels of efficiency and effectiveness in its operation and administration, as measured by reference to the best standards of comparable police services and report to Ireland's Minister for Justice and Equality on changes to improve efficiency in line with best international practice.