Before he became a politician, House Speaker Mike Johnson partnered with an anti-gay conversion therapy group

Speaker of the House Mike Johnson closely collaborated with a group in the mid-to-late 2000s that promoted "conversion therapy," a discredited practice that asserted it could change the sexual orientation of gay and lesbian individuals.

Prior to launching his political career, Johnson, a lawyer, gave legal advice to an organization called Exodus International and partnered with the group to put on an annual anti-gay event aimed at teens, according to a CNN KFile review of more than a dozen of Johnson's media appearances from that timespan.

Founded in 1976, Exodus International was a leader in the so-called "ex-gay" movement, which aimed to make gay individuals straight through conversion therapy programs using religious and counseling methods. Exodus International connected ministries across the world using these controversial approaches.

The group shut down in 2013, with its founder posting a public apology for the "pain and hurt" his organization caused. Conversion therapy has been widely condemned by most major medical institutions and has been shown to be harmful to struggling LGBTQ people.

At the time, Johnson worked as an attorney for the socially conservative legal advocacy group, Alliance Defense Fund (ADF). He and his group collaborated with Exodus from 2006 to 2010.

For years, Johnson and Exodus worked on an event started by ADF in 2005 known as the "Day of Truth" - a counterprotest to the "Day of Silence," a day in schools in which students stayed silent to bring awareness to bullying faced by LGBTQ youth.

The Day of Truth sought to counter that silence by distributing information about what Johnson described as the "dangerous" gay lifestyle.

"I mean, our race, the size of our feet, the color of our eyes, these are things we're born with and we cannot change," Johnson told one radio host in 2008 promoting the event. "What these adult advocacy groups like the Gay Lesbian Straight Education Network are promoting is a type of behavior. Homosexual behavior is something you do, it's not something that you are."

In print, radio and on television, Johnson, a Louisiana Republican, frequently disparaged homosexuality, according to KFile's review. He advocated for the criminalization of gay sex and went so far as to partially blame it for the fall of the Roman Empire.

"Some credit to the fall of Rome to not only the deprivation of the society and the loss of morals, but also to the rampant homosexual behavior that was condoned by the society," Johnson told a radio host in 2008.

Johnson's office did not respond to a CNN request for comment asking about his work with Exodus.

Exodus International joined ADF's Day of Truth event in 2006 and the groups worked together on promotional material for the event, including a standalone website which pointed users to Exodus' conversion ministries. Documents on that website cited the since-repudiated academic work in support of conversion therapy. Exodus Youth, the group's youth wing, promoted the event within its blogs.

Videos put out by Exodus and ADF on their standalone Day of Truth website featured two Exodus staffers speaking about how teens didn't need to "accept" or "embrace" their homosexuality. The videos featured testimonials of a "former-homosexual" and "former lesbian."

Documents on the website were not archived online but were saved by anti-conversion therapy groups such as Truth Wins Out in 2007 and 2008. The website featured a FAQ on homosexuality provided by Exodus and sold t-shirts saying, "the Truth cannot be silenced."

One video featured Johnson, who was later quoted in a press release on Exodus International's website ahead of the event, saying, "An open, honest discussion allows truth to rise to the surface."

Johnson promoted the event heavily in the media - through radio interviews, comments in newspapers, and an editorial. In interviews, he repeatedly cited the case of a teen who went to school after the Day of Silence wearing a shirt that read, "Be ashamed. Our school has embraced what God has condemned" and "Homosexuality is shameful." The teen was suspended and ADF represented him in legal action over the incident. The case was dismissed because the teen graduated, and the court found he no longer had standing to challenge the dress code.

"Day of Truth was really established to counter the promotion of the homosexual agenda in public schools," Johnson told a radio host in 2008.

Those who worked to counter ADF and Exodus at the time, said the event was dangerous to confused youth.

"This directly harmed LGBTQ youth," Wayne Besen, the executive director of Truth Wins Out and an expert on the ex-gay industry, told CNN. "This is someone whose core was promoting anti-gay and ex-gay viewpoints. He wouldn't pander to anti-gay advocates, he was the anti-gay and ex-gay advocate."

Randy Scobey, a former executive vice president at Exodus, who worked on the Day of Truth in the organization's collaboration with ADF, called the event one of his biggest regrets.

"It was bullying those who were trying to not be bullied," said Scobey, who now lives openly as a gay man. "That was one of the public ways that the Alliance Defense Fund worked with us."

Ties between Exodus and ADF extended beyond the event.

ADF, which has since changed its name to the Alliance Defending Freedom, touted Exodus International in promotional brochures in 2004, crediting it as an organization that "played an instrumental role in helping thousands of individuals come out of homosexual behavior."

Scobey recalled Johnson as quiet, but firm in his beliefs that homosexuality was wrong. He said Johnson and ADF provided crucial legal advice to Exodus and its "member ministries."

"We worked with them behind the scenes a lot," Scobey told CNN, saying the group offered them legal guidance over their ex-gay counseling. "They were very important to us as far as helping us to feel more secure legally and politically."

Exodus International stopped sponsoring the Day of Truth event in 2010, saying it became adversarial and counterproductive.

CNN's Em Steck contributed to this report.