Designed for a complement of 800 pupils, Kelso High School is a new build replacement secondary school which opened its doors on 14 November 2017.
Scottish Borders Council's executive member for children and young people Carol Hamilton said it was a "significant day" for the town.
She said it would "transform education" in Kelso and provide "much-improved facilities" not only for pupils but also for the wider community.
"The previous high school had served the town well since 1939 but there is no doubt the new facility will provide additional benefits," she said.
"I would like to congratulate the council's project team for the considerable efforts to get the new school completed on time, as well as the local residents and Kelso Races for their co-operation during the works.”
As a development of the learning hub concept, the school and sports complex is intentionally designed to appear as a single building providing a civic presence towards the town.
Three pitches, a sprint track, school garden and various outdoor teaching spaces complement the impressive educational and social facilities.
Together with The Newbattle Centre, Kelso High School forms the second phase of the £1.25bn Scottish Futures Trust (SFT) Schools for the Future programme, following on from the successful completion of Eastwood High School and The Lasswade Centre.
Kelso High School has been shortlisted for Development of the Year (Public Buildings) at the 2018 Scottish Property Awards.