He was appointed by Prime Minister David Cameron to the post as he finalised the first all-Conservative cabinet in 18 years.
Mr Mundell held on to his Dumfriesshire Clydesdale and Tweeddale seat in last Thursday’s general election despite a landslide of gains across the rest of Scotland by the SNP.
The Moffat-based politician was formerly Minister of State at the Scotland Office, most recently as number two to Liberal Democrat Alistair Carmichael in the coalition Government.
He regularly fielded questions in that job on the front bench at Scottish Questions in the Commons.
Fresh from his first cabinet meeting in Downing Street, Mr Mundell told DnG24 that he considered the appointment ‘a great honour.’
He said: “My priority is to ensure that the Scottish and UK Governments work constructively together in the best interests of the people of Scotland.
“It’s time to move on from bickering and politicking and instead take forward the issues and concerns important to people across Scotland.
“My first major task is to take through parliament the legislation that will enact the recommendations of the Smith Commission to increase the powers of the Scottish Parliament.
“I also want to be a strong voice for rural areas. Government at all levels has become far too urban orientated and the needs of those who live in rural communities must be taken into account more.”
Mr Mundell added: “My new role will not lead to any change in my commitment to my constituency or serving my constituents. Indeed I hope it will enhance it.”
The local MP, a former councillor, MSP and commercial lawyer remains the only Conservative MP north of the border.
Scottish Conservative leader Ruth Davidson welcomed the ex-Lockerbie Academy pupil’s appointment.
She said: “Having worked extensively across both Holyrood and Westminster he is quite simply the right man for the job.”