Background
McDonnell was born at Ennis, County Clare, Ireland, in 1863 to James McDonnell, a farmer, and his wife Elizabeth (née Bradish) and attended Ennis Christian Brothers School.
McDonnell was born at Ennis, County Clare, Ireland, in 1863 to James McDonnell, a farmer, and his wife Elizabeth (née Bradish) and attended Ennis Christian Brothers School.
At aged thirteen, he worked in a factory before returning to school and then in 1879 he was working for Gallagher Bros as an apprentice draper. By coincidence, a fellow employee was T.C. Beirne, who also went on to make a name for himself as a draper in Brisbane. In 1888, McDonnell helped organise the Shop Assistants" Early Closing Association and its associated publication, the Early Closing Advocate with articles by William Lane.
As a Labour candidate, he contested the seat of Fortitude Valley at the 1893 colonial election, losing to the Ministerialists, John Watson and John McMaster.
McDonnell stood again for the seat of Fortitude Valley at the 1896 election, this time polling enough votes to finish second to John McMaster in the two-member electorate, and therefore winning a seat. Within three months of his retirement from the Assembly in 1907, McDonnell was appointed by the Kidston ministry to the Queensland Legislative Council.
He remained a member until 1922 when the Council was abolished.
He remained a member of the Legislative Assembly for the next eleven years, declining to stand at the 1907 election.