Ms Billington began as deputy director of the diocese in 2002 and became director in 2010. 

She has overseen more than 50 Catholic schools and has been the driving force behind new programs, festivals, policies and professional development. 

Principal of St Joseph's College in Echuca, Kate Fogarty, said in a speech at Ms Billington's official farewell that she was a 'giant' of her profession. 

"We principals of Sandhurst know we have been well served by Phil’s leadership," Ms Fogarty said.

"Our school system has never been stronger, bigger, more outward-facing and more confident about encountering the challenges that lie ahead." 

Ms Billington said two federal and two state elections in four-and-a-half years had been a challenge during her time as director.

"I tend to see challenges as opportunities - opportunities for us to think in new ways, to look at well-being and education for all sectors."

Known as a champion of the arts, Ms Billington said one of her highlights was the arts programs she had led. 

"I’m a strong believer in the artistic development of children," she said.

Ms Billington said working in Catholic education was a way of responding to God's call in her life.

"I am a woman of faith and a strong believer in who we’re called to be for all people."

Ms Billington said what she would miss most after leaving her role was the people: students, parents, teachers and church leaders.

She said it had been a pleasure to call Bendigo home. 

"I’ve loved Bendigo.

“I think (Bendigo) is one of the most outstanding communities in Australia."

Ms Billington is retiring and moving back to her family in New South Wales but said she would remain active in Catholic education. 

School principal of St Francis Xavier Catholic College in the diocese of Sale, Paul Desmond, is Ms Billington's successor.