The denominational school has a high number of pupils who do not have English as a first language.
And it also has a high percentage of pupils on free school meals – 20% compared to the national average of 15%.
However, the proportion of pupils who passed five or more Highers jumped sharply from 4% in 2011 to 10%.
Headteacher Patricia Lennon believes a raft of measures has helped improve the school's showing, including dedicated study support, pupil tracking and a nurturing atmosphere.
She said: "There are pupils who may have difficulties as they mature and they may find aspects of school challenging.
"It is very important to make sure you know what these pupils need, both in terms of support, but also by designing a range of different courses that will spark interest.
"We are trying to build a culture of high expectations and positive aspirations to ensure pupils can be as successful as possible."
Mrs Lennon said a particular innovation this year was the introduction of a residential supported study weekend for pupils taking Highers.
A group of pupils went away for a weekend to a youth hostel in New Lanark where teachers held workshops on different aspects of courses.
She said: "That has been a revelation. Pupils are able to concentrate on specific areas of need and the close and more informal relationship which can be built up with teachers really helps them.
"We have also implemented a much more rigorous tracking and monitoring system from third year onward and that has been hugely successful.
"It highlights where pupils may be slipping and allows us to give them support at the right time and in the right place."