Complex sentence: In August of 2003, he was promoted to Deputy Director for Operations, where he served until being made director of NCIS after former director David L. Brant retired in December of 2005.
Split into simpler sentences: In august of 2003 he was promoted to Deputy Director for Operations. He served here until he was made director of NCIS after former director David L. Brant retired in December of 2005.