Donagh Mark Killilea born Tuam 1973 is married to Anna Reilly and has 3 children. Donagh is a member of Fianna Fail since 1987 serving as Chairman of the local party branch. Elected to the Fianna Fail National executive committee of 15 in 1996 and serving there for until 2011. Donagh Mark Killilea was elected to Galway County Council in 2014 and relected in 2019, serving as Mayor of Tuam Municipal District in 2015,2017,2022,2023. Donagh Mark Killilea is the 3rd generation member of his family to serve as an elected public representative father <nowiki>{{ [[Mark Killilea Jnr}}]]</nowiki> grandfather <nowiki>{{Mark Killilea Snr}}</nowiki>.
In 2023 he was elected as Chairman of the Regional Health Forum West (formally Western Health Board) a position held by both his father and grandfather. He is the only person to hold such a post as a 3rd generation member.