"WELCOME to the South Grafton Public School Sesquicentenary," students said as hundreds of community members, ex-students, teachers and special guests said as they walked into the grounds of South Grafton Public School.

For their 150th birthday celebration, students, teachers and the P&C had worked tirelessly on performances, displays and learning how to say sesquicentenary without stumbling.

But there was one very excited audience member sitting in the hall who was partially responsible for securing the building the children were performing in, John Thornton, who had been principal of South Grafton Public School for 22 years.

Having travelled from Ballina to celebrate the schools milestone anniversary, the former principal shared his memories from his years at South Grafton Public School.

"I believe I was a pretty progressive sort of bloke, and a lot of changes were needed, so we fought very hard," he said.

"I fought very hard for this hall, it took a lot of fighting and political influence to get it, because it wasn't the done thing normally."

Many ex-students would remember the two train carriages at South Grafton Public School, which were brought over from the train station under Mr Thornton.

"I ended up with two railway carriages... and we used one of those for a computer room, we were one of the first schools to do it... and the other was for small group stuff," he said.

"There has been a lot of changes made since too."

Mr Thronton retired after his time at South Grafton Primary School and looks back on his time there very fondly.

"I love the school," he said. "I put my life into it, we used to come back at night time and stay past midnight doing things and organising things.

"I've driven past the school many times since, and today to come inside and have a look at everything, I can't believe the changes, for the best.

"My time here, I remember very well, I remember the library and how we fought to get that organised and fixed up."

Mr Thornton couldn't stop singing the praise of the school, the principal Peter Hickey and the students.

"I feel proud of the school, and of the principals, so much has been done since I was here, I find it fascinating," he said.

"To know the school is existing and growing and is strong, it makes me feel really proud of the school... I think the children and students here need to be recognised as a very positive part of the school, and obviously the teachers here are good teachers."