SAN FRANCISCO -- A former San Francisco radio talk show host and Roman Catholic priest was sentenced to more than seven years in prison Thursday for distributing child pornography.

Bernie Ward, 57, frequently called the "lion of the left" for his staunchly liberal views, hosted a nightly news talk program and a program called "God Talk" on Sundays on KGO-AM 810.

The father of four was fired from the station after a federal grand jury indictment charging him with distributing child pornography was made public him in December.

Ward was charged after exchanging sexually explicit instant messages with a Stanislaus County woman who used the screen name Sexfairy2005 in December 2004. The woman called the police after Ward sent her a photograph of two children engaged in a sex act.

The woman provided police with transcripts of their conversation where Ward discussed various sexual scenarios with his children, including how he was aroused when his daughter walked in the bathroom while he showered, according to court documents.

"I find it extremely troubling that a parent would say the things he wrote in those messages," U.S. District Court Judge Vaughn Walker said before sentencing him to seven years and three months.

Federal prosecutor Steve Grocki said that dozens of pornographic images of children as young as 3 years old were found on Ward's home computer, including masochistic images of children bound and gagged.

"He traded in the currency of children's suffering," Grocki said in arguing for a nine-year prison term.

Ward's attorney, Doron Weinberg, citing the numerous letters of support Ward received after pleading guilty in May and his volunteer work, argued for a five-year prison sentence -- the mandatory minimum. Weinberg said Ward initially downloaded the child porn for research as a journalist.

"It's clear that it ended in a dark place," Weinberg said. "Bernie Ward is a good man."

The judge allowed Ward to turn himself into prison officials Friday.