Wayne Pacelle, who built the Humane Society of the United States into the country's most effective animal rights organization as its president and CEO, resigned Friday only a day after the board of directors had agreed to retain him despite allegations of sexual harassment. 

Kitty Block, who has been president of Humane Society International, HSUS’s global arm, was named acting president. 

Under Pacelle’s leadership, HSUS successfully pressured food and restaurant companies to require farms to change animal-care practices, particularly in hen and sow housing. However, HSUS has been rocked by allegations of workplace conduct in recent weeks and months. Another top executive, Paul Shapiro, left the organization in January amid allegations of sexual harassment, detailed Tuesday in a Politico story.

Seven members of the 31-member board resigned Thursday after the board voted to retain Pacelle, who had been president of the organization since 2004. 

The chairman of the board, Rick Bernthal, issued a statement Friday afternoon defending the decision to retain Pacelle, citing the results of the outside investigation the group had authorized. 

However.  HSUS subsequently issued another statement announcing that Pacelle had resigned. 

“The last few days have been very hard for our entire family of staff and supporters,” Bernthal said. “We are profoundly grateful for Wayne’s unparalleled level of accomplishments and service to the cause of animal protection and welfare.”

The second statement also said that board member Erika Brunson had resigned as well. She was quoted in a New York Times article Friday as downplaying the significance of sexual harassment. 

Block, a lawyer, joined HSUS in 1992, starting as a legal investigator and later moving into international issues. In 2007, she was promoted to vice president of Humane Society International, later to senior vice president, and last year became president.