With his wife holding the Bible, Robert Hunt was sworn into office Wednesday evening by Bullitt Circuit Judge Rodney Burress.
Hunt won a special election on Nov. 6 to fill the remaining two-plus years on the term as Second District magistrate.
Dan Kelty originally won the seat but resigned to pursue a career in law enforcement.
Rick Clements was appointed earlier this year to fill the seat until the general election, which Hunt won.
The Mount Washington resident will be in the seat Tuesday for his first Bullitt Fiscal Court meeting.