Government inspectors praised Calderglen High for its "outstanding achievement".
Minister for Learning Alasdair Allan visited the school to see first-hand the work being undertaken.
Mr Allan said: "It is an outstanding achievement for Calderglen to become the first school marked as excellent since criteria were strengthened in line with Curriculum for Excellence.
"I am delighted to offer my congratulations to all those involved in the school."
An inspection last month found the learning and achievement at the secondary to be "sector leading".
The inspection letter said that the "school community exemplifies high expectations, support and mutual respect".
It stated: "The school has developed highly-effective ways of ensuring all young people have the support they need to achieve well."
The letter said that "almost all young people" go on to further study, employment or training after leaving the school.
It also highlighted the high number of students who "perform and achieve extremely well in sporting and cultural activities".
Head teacher Tony McDaid said: "We are delighted with such a highly-positive report.
"We believe it reflects the commitment, drive and creative approaches which are pursued to achieve the very best for all of our pupils."