The Entertainment Software Association, the organization behind E3 and the group that lobbies on behalf of U.S. video game publishers, announced a change in leadership today. ESA president and CEO Michael D. Gallagher, who joined the organization in 2007, has resigned.

In his stead, Stanley Pierre-Louis, ESA’s senior vice president and general counsel, will serve as interim president and CEO. The ESA said it will search for a permanent replacement.

The reason for Gallagher’s departure was not announced.

Gallagher led the organization during a landmark First Amendment case, Brown v. Entertainment Merchants Association/Entertainment Software Association, that went before the U.S. Supreme Court. The 2011 ruling in that case struck down a California law that would have regulated the sale of video games based on their content. During his tenure, Gallagher also oversaw the transition of the annual Electronic Entertainment Expo from a media- and business-focused event to one that would later admit the public.

“Serving the video game industry and the ESA Board has been a tremendous honor,” Gallagher said in an official statement. “ESA is in a strong position to continue the work ahead. It has an excellent team, ample resources, state-of-the-art DC headquarters, and members who are fueling growth at fantastic levels. Together, we have delivered an unbroken string of victories in the states, on Capitol Hill, and before the U.S. Supreme Court, all of which bolster the industry’s ability to create and innovate. Extending and protecting that opportunity has been extraordinarily fulfilling.”