Tim Dowd, 66, who has also worked on episodes of Emmerdale and Heartbeat during his 30-year career, was recorded having intimate chats with an undercover police officer, who was posing as a teenager named Chantelle.
A jury heard how Dowd, of Chatsworth Grove in Harrogate, North Yorkshire, asked her for phone sex and requested images of her breasts over a four-day period last January.
In a statement issued following his conviction at Leeds Crown Court, an NSPCC spokesman said: "Dowd's attempt to incite a child to engage in sexual activity shows he has a sick desire for sexual contact with children - that the 'victim' in this case was an undercover officer doesn't take away his intentions, or the fact that he acted on them."
During the former freelance director's three-day trial, jurors were told how he met the officer, who was employing the username Chantelle13Cymru, on a site named Lycos Chat, before quickly moving on to WhatsApp.
The officer, who gave evidence anonymously, said she had to input an age above 16 in order to join Lycos, but said that she was able to pose as a 13-year-old.
In his defence, Dowd claimed that he believed that the person he was talking to was an adult pretending to be underage as part of a sexual fantasy, despite frequently seeking clarification on her age.
Jurors heard how he lost his job shortly after being arrested at a property in East Keswick, Leeds, having spoken with the officer between January 12 and January 15 last year.
The NSPCC spokesman added that it was hoped that Dowd's conviction "sends a message to others that crimes against children will not be tolerated."
On Friday, the children's charity called for a "Wild West Web" clampdown after it obtained figures suggesting that children as young as five were falling victim to grooming and abuse nationwide.
Using data from across the country, it found 5,161 reports of sexual communication with a child were recorded in the space of just 18 months between April 2017 and September last year.
Dowd was convicted on Thursday of three counts of attempting to incite a child to engage in sexual activity and one count of attempting to engage in sexual conversations with a child for the purpose of sexual gratification, a Leeds Crown Court spokeswoman said.
He will be sentenced on March 21.