A week after he was sworn into office, the president of the Board of Education in Chicago resigned on Thursday over social media posts from the past year that elected officials criticized as anti-Semitic and misogynistic and that espoused a conspiracy theory about the Sept. 11, 2001, attacks.

The posts by the former president, the Rev. Mitchell Ikenna Johnson, were “not only hurtful but deeply disturbing,” the mayor of Chicago, Brandon Johnson, said on Thursday.

The mayor said that he had asked for Mr. Johnson’s resignation, adding, “I want to be clear: Antisemitic, misogynistic and conspiratorial statements are unacceptable.”

In an interview on Friday, Mr. Johnson, 64, the former board president, defended his track record as an ally of the Jewish community, citing his past work with the Simon Wiesenthal Center, a Jewish human rights group.

“The people that have reacted strongest are choosing to forget the work I’ve done in that community, and that is a darn shame,” he said.

He said he apologized for his comments, which “could have been tempered with language that is not meant to be seen or heard as anti-Semitic.”