His father, Dan Patrick Flanagan (of Irish descent), practiced law in Lafayette.
[1] After graduating from high school, he enlisted in the Armed Forces and served as a sergeant in the Field Artillery Branch during the First World War.
[1][2][3] After graduation, Flanagan returned to Frankfort and practiced law there until 1924, serving as Deputy Prosecutor for Clinton County from 1921 to 1922.
In 1936, he became Chairman of the Allen County Republican Party Central Committee, overseeing several successful local campaigns.
[1][2][3] Flanagan was appointed a judge of the Indiana Court of Appeals in 1941 by Governor M. Clifford Townsend.
[2][3] In 1953, Flanagan was appointed to the Indiana Supreme Court by Governor George N. Craig following the resignation of Justice Paul G.
They had a son, Daniel Jr.[3] Flanagan died in Fort Wayne in 1960, at the age of 60, following an illness of several months.