St Augustine's RC High School was due to be officially opened as part of a 180 million council rebuilding programme.
The school boasts a purpose-built theatre and roof-top terraces with views over the surrounding countryside.
Cardinal O' Brien said ahead of the event: "I am intensely looking forward to the formal opening of St Augustine's RC High School.
"I myself received the latter part of my secondary education in Edinburgh at Holy Cross Academy in Edinburgh – the predecessor of St Augustine's RC High School.
"Consequently, this will be a nostalgic occasion for me – and yet one which I realise will be vitally important for the ongoing education and formation of many fine young people."
City education leader Marilyne MacLaren added: "It is exciting to see our latest new school open in the city. The new building will encourage pupils to learn, prosper and ultimately succeed in the future.
"This school will also benefit the local community, with plenty of new facilities for locals."
The high school was founded in August 1969 after Holy Cross Academy and St Andrew's Junior Secondary merged.