S. I. Newhouse Jr., who as the owner of The New Yorker, Vogue, Vanity Fair, Architectural Digest and other magazines wielded vast influence over American culture, fashion and social taste, died on Sunday at his home in Manhattan. He was 89.

His family announced his death.

Mr. Newhouse, known as Si, and his younger brother, Donald, inherited an impressive publishing empire from their father, Samuel I. Newhouse, and built it into one of the largest privately held fortunes in the United States, with estimates of the family wealth running over $12 billion at the turn of the 21st century. While Donald led the more profitable newspaper and cable television operations, Si took charge of the more glamorous magazine division, Condé Nast.

Much of that glamour was created under Si Newhouse’s direction. Though he was a shy man and often painfully awkward in public, Mr. Newhouse hired some of the most charismatic magazine editors of the late 20th century, among them Tina Brown and Graydon Carter at Vanity Fair and Diana Vreeland and Anna Wintour at Vogue, and encouraged them to behave like the celebrities they extolled in his publications.

It helped that he rewarded them with salaries, expense accounts, clothing allowances and housing loans that were the envy of their peers. Newhouse editors also enjoyed spectacularly generous budgets at their magazines, which often ran deep in the red for years before turning profits.