Mr. Holtzbrinck’s actions come two days after his fellow board members voted in favor of Mr. Murdoch’s $5 billion bid to purchase Dow Jones. Mr. Holtzbrink abstained from the vote.

Subsequently, he penned a letter to his fellow board members, dated July 19, explaining his mindset.

“Although I'm convinced that News Corp. offer is very generous in financial terms, I'm very worried that Dow Jones unique journalistic values will long-term strongly suffer after the proposed sale,” wrote Mr. von Holtzbrinck.

“I cannot prove that my worries are right,” he added. “I can only refer to News Corp. business practices in the past, can only refer to Jim Ottaway's article in the Journal, etc. I do not believe that the "Special Committee" can finally prevent Murdoch from doing what he wants to do, from acting his way.”

In 2002, Forbes ranked Mr. Holtzbrinck’s family as the 60^th richest in the world. According to the piece, Mr. Holtzbrinck, his sister, and his half-brother inherited the von Holtzbrinck publishing empire—a diverse company with roughly $2 billion in annual sales—in 1948 from their father Georg von Holtzbrinck.

The company’s flagship publication is a German business paper Handelsblatt. In the United States, the publishing empire includes Farrar, Straus & Giroux, Henry Holt, and Scientific American.

Reached on Thursday evening, James Ottaway Jr. said that he wasn’t in the least bit shocked by Mr. Holtzbrinck’s decision to step down in protest. “I’m not at all surprised,” said Mr. Ottaway. “He runs newspapers in Germany that are of the very highest standards and quality.”