Julian was born in Flat Rock, North Carolina, to Julian Mitchell and Caroline Phoebe Pinckney, both of Charleston.
He attended the McCabe School in Petersburg, Virginia, Harvard College and the University of Virginia Law School. He was admitted to the South Carolina Bar in 1890 and entered his father’s firm of Mitchell and Smith, of which H.A.M. Smith (later a United States District Judge) was a partner. He served in the South Carolina Legislature and maintained an active law practice for 41 years.
He married Belle Witte and they had two sons, one of whom was a lawyer who practiced with his father in Mitchell and Horlbeck.
In 1931, he became President (and later, Chairman) of the South Carolina National Bank and helped it survive the 1933 crisis without a loss to its depositors or stockholders.
With keen public spirit, he took an active behind-the-scenes interest in politics. His depth of intellect, persuasive advocacy and devotion to basic principles of law made him an able counsellor and an outstanding trial lawyer.