Johns Hopkins APL Director Ralph Semmel to Conclude ‘Extraordinary and Transformative’ Tenure in 2025

Johns Hopkins Applied Physics Laboratory (APL) Director Ralph D. Semmel has announced that he will step down from his role in July 2025, marking the conclusion of 15 remarkable years leading the nation’s largest university affiliated research center.

“Serving alongside APL’s dedicated staff members has been the greatest professional honor of my life,” said Semmel. “My colleagues have made amazing contributions to many of the most daunting challenges facing our nation, and taken what was already a remarkable organization to incredible new heights. That is what every APL director strives and hopes for during their tenure, and I could not be prouder of all we have achieved.”

“Without any sense of hyperbole, we regard the Lab’s successes under Ralph’s leadership as nothing less than extraordinary and transformative,” Johns Hopkins University (JHU) President Ron Daniels said. “We will have ample opportunity in the year ahead to recognize and celebrate Ralph’s many contributions to APL, and we are pleased — and relieved — that he has committed to one more year as director and to keeping his sights firmly trained on maintaining APL’s momentum as we conduct the search for his successor and make this important transition.”

A national search for Semmel’s successor has commenced, led by a search committee composed of JHU leaders and members of APL’s Board of Managers. The committee is co-chaired by Adm. Gary Roughead (U.S. Navy, retired), former chief of naval operations, JHU trustee and member of the APL Board; and Edward Schlesinger, Benjamin T. Rome Dean of the JHU G.W.C. Whiting School of Engineering. The firm Odgers Berndtson will assist in the committee’s search.

“APL is a treasured national resource, and Ralph’s profound impact on the Lab, its staff and sponsors, and the breakthrough research and technology it delivers has been remarkable,” said APL Board of Managers Chair Heather Miller, who is also a member of the JHU Board of Trustees. “Under Ralph’s exceptional and inspiring leadership, the Laboratory and its dedicated people have added to their storied tradition as an innovation powerhouse, creating game-changing solutions to address critical challenges, and making the world a better and safer place. Its new director will be building on an exceptional foundation as they take the helm.”

During Semmel’s tenure as director, which began in 2010, the Laboratory sharpened its strategic focus and created new initiatives to foster greater innovation, accelerating APL’s contributions to the Department of Defense, NASA, the Intelligence Community and other federal agencies. Semmel led APL as it developed game-changing breakthroughs in domains including air and missile defense, cyber, artificial intelligence and autonomy, hypersonics, space science and engineering, biomechanical engineering, undersea systems, special operations, multi-service strategic systems, biothreat defense and materials science.

Throughout his almost 40 years at APL, Semmel has also contributed to the national security strategy and R&D communities as a member of the Defense Science Board, the U.S. Strategic Command Strategic Advisory Group and various panels of the National Security Agency (NSA) Advisory Board; he is currently a member of the Council on Foreign Relations. Semmel has served as chair, co-chair or editor for numerous academic graduate programs, journals, conferences and committees. He is a West Point graduate with master’s degrees in computer science and systems management and a Ph.D. in computer science.

Since its founding in 1942 to aid a nation at war, APL has had eight directors. Semmel is the second-longest-serving head of the Laboratory, trailing only its third director, Ralph Gibson, who held the position for 21 years (1948-1969).

“I look forward to our next year together, as we still have much to do,” Semmel wrote in a note to APL’s staff. “The challenges facing our country are immense and becoming increasingly complex. As we have since APL was founded in 1942, we continue to answer the call to develop highly innovative and novel solutions that enhance the security and well-being of our nation. As we look ahead, let us stay focused and true to our core purpose of making critical contributions to critical challenges.”