Born in Darver, County Louth, McDonnell first played competitive Gaelic football with the Darver Volunteers club. He won a junior league medal in 1952 before winning a county junior championship medal in 1956. From 1961 onward McDonnell played with the newly-formed St Joseph's club.[4]
McDonnell made his debut with the Louth senior team during the 1948 championship. Over the next ten seasons he enjoyed much success, culminating with the winning of an All-Ireland medal in 1957. He also won four Leinster medals. McDonnell retired from inter-county Gaelic football in 1958 but returned for one final season in 1960.[1]
In retirement from playing McDonnell became involved in team management and coaching. At inter-county level he was a selector with the Louth senior team during the 1960s. McDonnell later managed St. Joseph's to a county intermediate championship title in 1990.[4]