Jeffrey Bruce Klein, one of four journalists who in 1976 founded the magazine Mother Jones, rooting it in the crusading left-wing politics of the 1960s, and who returned in 1992 as editor in chief to rebrand it for younger, more digital readers, died on March 13 at his home in Menlo Park, Calif. He was 77.

His sons, Jacob and Jonah, said the cause was complications of a nerve disease.

Mr. Klein was an East Coast transplant to the Bay Area, drawn in the midst of 1960s counterculture by the possibility that the era’s anti-establishment character could continue to drive the region’s lively left-wing journalism.

In 1974 he joined Adam Hochschild, Paul Jacobs and Richard Parker, all editors at the progressive magazine Ramparts, to plan a publication that would expand the left’s focus on government malfeasance to include corporate muckraking and the role of money in politics.

They called it Mother Jones, in honor of the fiery labor leader Mary Harris Jones. Working from a cramped office above a McDonald’s in San Francisco, they produced their first issue in 1976.

Mr. Klein was officially the magazine’s literary editor, though in practice he commissioned writers of all kinds.