David Hudghton, of Wharfedale in Filey, was sentenced to 15 years in prison and a further year on licence at Doncaster Crown Court on Thursday.
He pleaded not guilty to all charges, but a jury found him guilty of eight charges of sexually assaulting a child under 13 and five charges of causing a child to engage in sexual activity.
The ex-Scarborough borough and Filey town councillor was also placed on the sex-offenders’ register for life and made subject to a sexual-harm prevention order, also for life.
Speaking about the sentence handed to Hudghton, Detective Inspector Glenn Kelly of Scarborough CID said: “Hudghton has caused untold harm to the victims and the families involved in this case, not only through his depraved actions but also by refusing to accept his guilt, forcing them to have to live through a Crown Court trial.
"I’d like to commend the victims and their families on their bravery in coming forward and their resilience throughout the investigation and prosecution process.
“We know that the sentence handed to Hudghton can never erase the pain he has caused, but we hope it allows the victims and their family to have some element of closure on what can only be described as a traumatic and distressing experience for them.
“The protection and safeguarding of children is of paramount importance to North Yorkshire Police. My colleagues and I will ensure anyone who has exploited the most vulnerable in our society will face justice.”