The chairman of neurosurgery at Brigham and Women’s Hospital, who in February was found guilty of workplace hostility in a $1.6 million sex discrimination lawsuit, will resign from his position at the end of the month.

The resignation of Arthur L. Day, who has served as chair of neurosurgery at the Harvard affiliate since July 2007, was announced in an e-mail to the hospital’s community Monday.

“A decision like this is never an easy one,” Day wrote in an e-mail to his department. “In each of our lives, we reach a crossroad—a time for transition—to pursue other opportunities.” The e-mail did not give a specific reason for his departure.

Day could not be reached for comment for this story.

Sagun Tuli, the plaintiff and the hospital’s first female spine neurosurgeon, was granted $1.6 million by a jury in Feb. 2009 after refusing an earlier settlement with Brigham and Women’s.

The award included $1 million for a hostile work environment under Day  and $600,000 for damages incurred from hospital retaliation when Tuli voiced her concerns.

The hospital was found not guilty on charges of pay, research, and promotion discrimination, and was also found not guilty of discriminatory intent during an employee evaluation.

The suit began in Dec. 2007, just months into Day’s tenure as department chair, when Tuli filed an injunction after a hospital credentials committee that included Day threatened that her credentials would be revoked unless she agreed to undergo a psychiatric evaluation.

The court granted the injunction and allowed Tuli to retain her credentials without receiving psychiatric evaluation.

A. John Popp—who currently serves as program director for the neurosurgery residency program at Children’s Hospital Boston, Brigham and Women’s, and Harvard Medical School—will become chair of the neurosurgery department in January.

Hospital spokesman Kevin Myron wrote in an e-mailed statement yesterday that under Popp’s leadership, the hospital hopes “to continue to build on a department whose future holds a bountiful promise to make a difference in the lives of those who depend on us.”

—Staff writer Alee Lockman can be reached at alockman@fas.harvard.edu.