Which synagogue leader in Corinth believed in the Lord along with his whole household?

Answer: Crispus

Crispus, the synagogue leader, and his whole household believed in the Lord, and many Corinthians believed too.

“Crispus, the synagogue leader, and his whole household believed in the Lord. And many of the Corinthians who heard the message believed and were baptized.”— Acts 18:8 (BSB)