John Thornton, a financier who leveraged his wealth and influence to embark on the seemingly quixotic mission of reviving local journalism in a time of crisis, by founding The Texas Tribune, a seminal regional nonprofit news organization, and the American Journalism Project, which supports local digital newsrooms around the country, died on Saturday in Austin, Texas. He was 59.

His death, by suicide, followed a long mental health struggle, a spokesman for the American Journalism Project said.

Mr. Thornton helped change the financial model for sustainable local journalism when, in 2009, he founded The Texas Tribune, a member-supported, digital-only, nonpartisan media organization. The Tribune, which began with 11 reporters and editors focusing largely on Texas state politics, now has a newsroom of more than 50 staff members covering local issues in all 254 counties in the state, in addition to a congressional reporter in Washington.

That success inspired Mr. Thornton to try to replicate the model nationwide with the American Journalism Project, a “venture philanthropy” effort, as he termed it, based in Washington. He started it in 2019 with Elizabeth Green, a founder of Chalkbeat, a nonprofit education news organization.

Both The Tribune and the journalism project aimed to fill the gaps created by the decline or disappearance of local legacy news organizations in an era when more Americans were turning to far-flung corners of the internet and social media for news — or something resembling it. That decline had depleted the ranks of reporters who might have otherwise ferreted out local corruption and tracked the billions spent by city and state governments.