Walter H. Annenberg, media magnate and prolific philanthropist who gave $25 million to Harvard undergraduate education, died yesterday of pneumonia.

He was 94.

Annenberg, whose media company Triangle Publications once included print, radio and television holdings, focused his charitable efforts on education.

Over the years, he gave billions to various schools, scholarship funds, and educational organizations, including the University of Pennsylvania and the University of Southern California.

In 1993, Annenberg donated $500 million toward public school reform.

But Annenberg also maintained a special relationship with Harvard presidents for decades, according to Andrew K. Tiedemann, communications director for alumni affairs and development.

He was especially close to former University President Neil L. Rudenstine. It was in 1993, under Rudenstine’s presidency, that Annenberg made his most significant financial contribution to the University.

Annenberg was so impressed with the vision that Rudenstine communicated in one of their conversations that he suggested a gift of $25 million, according to Tiedemann.

Rudenstine determined that funds would go to undergraduate education: $10 million toward undergraduate scholarships, $3 million to fund undergraduate seminars, and $12 million to convert part of Memorial Hall into a dining hall for first-year students. Named in honor of Annenberg’s late son, Roger Annenberg ’62, the hall has become a campus icon and an essential part of the undergraduate experience at Harvard.

The University recognized Annenberg’s contribution and commitment to education by awarding him an honorary degree in 1996.

“Walter Annenberg was a valued, loyal advisor and an extremely generous benefactor,” Tiedemann said. “His gift will provide scholarships for generations of undergraduates. His legacy will be long-standing. He will be sorely missed.”

Annenberg enjoyed an immensely successful business career and public life. He inherited The Philadelphia Inquirer and two racing publications from his father, Moses L. Annenberg, and proceeded to build on his holdings. His Triangle Publications became a media power and included such publications as Seventeen Magazine and TV Guide.

Annenberg’s net worth was estimated at about $4 billion in 2002, according to Forbes magazine.

Annenberg also enjoyed close ties to U.S. presidents from Dwight D. Eisenhower onward. In 1969, Richard Nixon named Annenberg ambassador to the United Kingdom. Ronald and Nancy Reagan used to frequent his California estate. In 1986, Annenberg was awarded the Medal of Freedom, the nation’s highest civilian honor.

Annenberg was also an art aficionado who in 1991 pledged his extensive collection of Impressionist and post-Impressionist masterpieces to the New York Metropolitan Museum of Art.