The school, on Maryhill Road in the West End, is a haven for 45 children and young people with severe learning difficulties and autism.
Being a pupil at the school - whether a day pupil or residential - can be life-changing.
Almost all pupils will have tried a number of other placements before settling in East Park.
Head teacher Linda Gray has been working with autistic children for more than 20 years. She said: "Our children have very severe difficulties, which are often too much for additional support schools to cope with.
"This means that some of our pupils have been in up to five other schools before they reach us. This is really unsettling for them and very stressful for parents.
"However, we really have seen it all here and we have very high-level supports in place to cope with whatever our pupils need from us."
East Park can take pupils aged five to 25 - from primary school right through to a programme for young people called Work Mates.
East Park is a charity, which earns money from donations and Scottish Government funding, and previously cared for children with wide-ranging physical disabilities.
Its pupils came to the school with difficulties as diverse as blindness and muscular dystrophy.
But in 2000, due to the changing needs of children, East Park began taking youngsters with the most complex additional support needs - and developed a specialism in autism.
In 2007 it received Autism Accredited status - one of few schools in Scotland to do so.
East Park is now highly rated in the field and teachers come from around the country to observe working practices.
It is also an accredited SQA centre where teachers can sit for additional qualifications.
In June 2013 the school was awarded the Scottish Institute of Residential Care Reaching Higher award.
Executive director Judy Cromarty, who joined the school in 2012, said: "Our teachers pride themselves on providing sector leading information and research to others across Scotland. We really are a national resource.
"But at the same time we are at the heart of Maryhill and the community here has taken us to its heart.
"I've found since coming here from Edinburgh that you can't speak to anyone without them knowing someone who has a connection to East Park."
Judy said the school receives great support from the local community as well as links with Partick Thistle, Strathclyde University and local businesses.
And the artist John Lowrie Turner completed his final year dissertation from Glasgow School of Art on Art Therapy - carried out at East Park.
Some of the paintings of the school's pupils are on display in Clydebank Town Hall.
Today, children are referred to East Park from other schools, by social work services, the Children's Panel and child psychologists.
Teachers work with youngsters in small classrooms that are brightly coloured and compact to allow pupils tailored tuition.
East Park now has the highest number of pupils it has ever had and its residences are at capacity.
As it marks its 140th anniversary, bosses are looking to the future - and plans for expansion.
They hope to develop the Maryhill site and create a £2.5million extension on the site of a derelict building adjoining the school.
This would create a new teaching space and additional residential places.
Judy added: "We are very much looking to the future and to developing the quality of work we have been carrying out at East Park.
"I work with the portrait of William Mitchell, our founder, looking at me from the wall and I like to think he keeps me in line - and that he would be impressed with what we have achieved.
"Although we are 140 years old the ethos of the school is still the same and there are still similarities between the school's early years and now.
"The clearest link is that the education and well-being of our children has always been our principal concern and that is what guides us."
TOMORROW: How the school transformed our children's lives