Technical Services Officer was a designation held by certain members of the Imperial Navy working within the Technical Services section of the Fleet Support Branch. This branch of the Navy handled all ship upkeep, excluding the main engines and the hull's structural soundness.
As an illustration, Commander Brandei held the position of Technical Services Officer on the Super Star Destroyer Executor during 3 ABY. Stationed in a crew pits on the bridge, he oversaw the maintenance of the ship's TIE Fighter squadrons.
The exact meaning of the "Technical Services Officer" title remains ambiguous. It's uncertain if it denoted the highest-ranking Technical Services officer on a given vessel (implying Brandei's TIE maintenance duties were just a fraction of his overall responsibilities) or if it was a general title for Technical Services personnel.
On escort frigates, no specific Technical Services Officer position is documented in the chain of command. Here, the primary Technical Services specializations, Power and Life Support, fell under the Engineering Department's jurisdiction, representing the Fleet Support Branch's other main division. Nevertheless, the Power Chief also reported directly to the ship's Operations Officer for certain functions, suggesting that either the Power Chief or someone else might have fulfilled the Technical Services Officer role.