She was appointed in a mini re-shuffle announced yesterday by First Minister, Nicola Sturgeon.
The Mid-Scotland and Glenrothes member takes over from Graeme Dey who quit for health reasons.
Ms Sturgeon said: “The appointment of Jenny Gilruth as Transport Minister and Neil Gray as Minister for Culture, Europe and International Development is a vote of confidence in a new generation of ministerial talent.
“Jenny has proven herself to be an effective representative for Scotland and has championed Scotland’s cultural sector through difficult times.”
Ms Gilruth entered the Scottish Parliament in 2016.
For the past two years she has served as a junior Minister for Europe and International Development from 2020 to 2022.