Neil Harris had taught at a dance school in Erdington, Birmingham, from 1957 until earlier this year.
He was investigated after a woman came forward two years ago. The woman, who was taught by him in the 1980s, conducted a Google search and identified Harris as still being an active teacher of a dance studio.
She told police Harris had sexually touched her when she was aged between nine and 13-years, on several occasions.
More people were identified by officers as an investigation was launched and allegations of further inappropriate touching and abuse followed.
In March, Harris, of Manta Road, Tamworth, was charged with 21 counts of indecent assault on seven children.
And yesterday, following a three-week trial at Birmingham Crown Court, he was found guilty of seven counts of indecent assault relating to four girls.
DC Nichola Thomas, said: “The bravery and courage of the individuals in coming forward is admirable and I am so very thankful to those who have reported their experiences to us.
“I would like to reassure anyone who has been through anything similar or feels someone of authority may have acted inappropriately towards them in the past, that we will investigate and prosecute those responsible.
“I would urge anyone who has ever thought about speaking to police about sexual abuse, to come forward. We are here to help you.
“If you want to speak to me about this case in particular, please don’t hesitate to contact me on 101 ext 845 6170."
Survivors of sexual abuse can also speak to the NSPCC 24-hours-a-day on 0808 800 5000.
Harris is due to be sentence on January 19.