Tabor Vaux, who won the County Council District 9 seat in a special election last week, was sworn into office Monday morning.
Vaux won the seat in a Republican primary held Jan. 28. Because no other party fielded a candidate and no write-in or petition candidates came forward, he was named the seat winner Friday.
The seat was vacated by former Chairman Weston Newton, who was elected to the S.C. House of Representatives in November.
Vaux, 29, is the youngest seated council member. He is a graduate of Hilton Head Island High School, The Citadel and the Charleston School of Law.
Judge Carmen Mullen administered the oath Monday morning; Vaux was accompanied by his wife, Erin.