Joni Lamb, the president of Daystar Television Network, a televangelism broadcaster she founded with her husband, Marcus Lamb, turning their family into stars of Christian entertainment, died on Thursday. She was 65.

In an announcement posted on Daystar’s website, the company described the cause as “serious health matters” exacerbated by a recent back injury. It did not say where she died.

On a trip to Jerusalem in 1983, shortly after the couple married, Mr. Lamb visited the Mount of Olives and felt God telling him to move to Montgomery, Ala., and start a Christian TV station. He and Ms. Lamb poured their energy and modest finances into the effort and began appearing on the air two years later.

By the time they founded Daystar — in Texas in 1997 — they were experienced entrepreneurs and performers. After just a few years, they owned 24 stations around the country. By 2010, they had become the second-largest Christian broadcaster, after Trinity Broadcasting Network, and were reaching more than 200 countries, The Dallas Morning News reported.

Compared with other televangelists, the Lambs “are younger and come across as more ordinary folks,” David Clark, the president of a rival Christian broadcaster, told The Fort Worth Star-Telegram in 2001. “They come across as being sincere.”

Mr. Clark added: “Marc is sharp, and his wife, Joni, is a big asset.”

The Lambs frequently appeared on their own network in a talk show format, discussing the pleasures and challenges of domestic life in a Christian idiom. Ms. Lamb, who liked to break into song, was Daystar’s leading talk show host, over the decades moderating shows like “Taking a Break With Joni” and “Joni Table Talk.” She would often be surrounded by other female regulars, putting questions to a male guest who had wisdom to impart.

The prominent pastor Jentezen Franklin visited earlier this year, for example, to discuss his new book, “The Power of Short Prayers.” The conversation slipped easily into evangelism.

“For someone watching right now: You’ve been listening; God’s opened your heart,” Ms. Lamb said. “In fact, your heart’s already been opened for some time, as you’ve been looking, searching, and you tried everything else. Always say, ‘Why don’t you try Jesus?’ A simple prayer: That will change your life for eternity.”

During the episode she was flanked, as she often was, by her two daughters, Rachel Lamb Brown and Rebecca Lamb Weiss, and referred to her husband by his first name, as if the viewers at home were family friends.

In 2021, Mr. Lamb died, at 64, of Covid-19, after having frequently suggested that people should pray instead of getting vaccinated. Ms. Lamb announced his death on air.

The travails of the Lamb family were often incorporated into the station’s programming. In 2010, Mr. Lamb admitted on live TV to an extramarital affair and described an attempt to extort millions of dollars in blackmail.

“Christian TV took a soap opera turn,” The Dallas Morning News wrote of the episode.

In 2020, Daystar returned a $3.9 million Paycheck Protection Program loan after the CBS program “Inside Edition” investigated the company’s purchase of a Gulfstream jet used by the Lamb family for beach and golf trips.

Four years later, a panel of Ms. Lamb’s talk show regulars questioned her on air about an accusation by her son, Jonathan, that there had been a coverup of a family member’s sexual molestation of his infant daughter. Ms. Lamb denied that any abuse had occurred, and after an investigation, no charges were filed.

Joni Lynn Trammell was born on July 19, 1960, in Greenville, S.C., where she grew up. Her father, Billy Frank Trammell, worked for a local refrigeration and heating company and would evangelize with friends he made playing basketball. Her mother, Sandra (Hudson) Trammell, competed in the Miss Greenville beauty pageant.

The Lambs met at a Greenville church in 1980, when Mr. Lamb, a traveling Pentecostal preacher, was visiting. They married in 1982.

Their early investments in TV stations came fortuitously, at a time of deregulation that The Star-Telegram would describe as “market bottom.” They later made money buying and selling small broadcast towers, and selling airtime to ministries and churches.

In 2023, Ms. Lamb married Doug Weiss, a sex therapist who became a co-host on Daystar. He survives her; other survivors include her three children and several grandchildren.

On air earlier this year, Ms. Lamb told viewers that the Christian faith guaranteed a posthumous reward.

“When you pray that prayer, and you receive Jesus, he forgives your sins,” she said. “When you die, you’re going to heaven.”