The First Minister announced Ms McAllan, who had previously been part of her team of special advisers, as the new minister for environment, biodiversity and land reform.
She was elected to the Scottish Parliament in the May 6 election to represent the Clydesdale constituency.
George Adam, who has been an MSP since 2011 and was the SNP group chief whip at Holyrood, has been made the new minister for parliamentary business.
Thomas Arthur, who had been deputy whip, was handed the role of public finance minister.
The trio are among 15 junior ministerial appointments made as the First Minister carried out a wide-ranging reshuffle of her top team.
Angela Constance remains as drugs minister, a post she was appointed to in December last year, with Ivan McKee remaining as trade minister.
Richard Lochhead, who had been responsible for further and higher education, switches to become the new minister for just transition, employment and fair work.
Maree Todd, who served as children’s minister before the election, becomes minister for public health, women’s health and sport, while Kevin Stewart is moved from housing to be the new minister for mental wellbeing and social care.
Clare Haughey, who was previously mental health minister, has been appointed as the minister for children and young people, while Jamie Hepburn is moved from business minister to take over at further and higher education.
Graeme Dey, who had been veterans minister and parliamentary business minister, is the new transport minister, and Ben MacPherson, who had been rural affairs and environment minister, has been moved to social security and local government
Ash Denham remains as community safety minister, with Christina McKelvie also staying in her post as minister for equalities and older people.
There is no change either for Jenny Gilruth, who is still minister for Europe and international development.
The junior ministerial roles were announced after Ms Sturgeon had earlier unveiled a 10-strong Cabinet that included the addition of SNP heavyweight Angus Robertson and former health secretary Shona Robison.