Patrick M. Shanahan

The White House announced on May 9, 2019, that Trump intended to nominate Shanahan as the Secretary of Defense. That decision was reversed on June 18, 2019, when Shanahan said that he was withdrawing, and Trump announced that he would be making Mark Esper the acting U.S. Secretary of Defense. Shanahan's last day in that position was June 24, 2019.

President Trump initially announced that Shanahan would be elevated on February 28, 2019 to Acting Defense Secretary, when the Mattis resignation was originally to become effective. But a follow-up Trump Twitter announcement on December 23, 2018 stated that Shanahan would be elevated two months prior to the resignation date announced by Mattis. Trump accelerated Mattis's departure date after reportedly becoming angered by the media coverage of his resignation letter, due to language in Mattis’ resignation letter which criticized Trump's worldview. Shanahan assumed the office on January 1, 2019.

Shanahan made an unannounced trip to Afghanistan on February 11, 2019 meeting with President Ashraf Ghani, the country's chief executive Abdullah Abdullah, and defense minister Asadullah Khalid during the first few hours of his trip.

Shanahan visited the US–Mexico Border on February 23, 2019 with Chairman of the Joint Chiefs of Staff USMC General Joseph Dunford and Commander of the United States Army Corps of Engineers Lt. Gen. Todd T. Semonite for joint assessments with Border Patrol, DHS, and others.

In late March 2019, news sources reported that Shanahan was under investigation by the Pentagon's Office of Inspector General because of allegations he improperly advocated on behalf of his former employer, Boeing Co.

In a May 2019 internal memo, Shanahan ordered new restrictions on how information about global operational plans and orders are shared with Congress, such that summaries are provided rather than an actual plan or order that was requested.

On May 9, 2019, the White House announced that President Trump would nominate Shanahan as his second defense secretary, despite skepticism and even hostility from lawmakers and officials within the Department of Defense. However, Shanahan withdrew from the confirmation process in June, following increased public scrutiny of several incidents and allegations of domestic violence involving Shanahan's ex-wife and son. In a tweet addressing the withdrawal of the nomination, President Trump said that Shanahan intended to "devote more time to his family."

On March 16, 2017, President Trump announced his intent to nominate Shanahan as the 33rd Deputy Secretary of Defense, the Pentagon's second-highest civilian position. Trump nominated Shanahan to lead plans to increase the size of the military.

Shanahan's Senate confirmation hearing took place on June 20, 2017. During the hearing, Senator John McCain, a proponent of providing arms to Ukraine, threatened to block Shanahan's nomination over his response in a written statement about whether or not the U.S. should provide such weapons to Ukraine. Shanahan said he did not have access to classified military information in order to make a decision on the matter.

Robert O. Work, the Deputy Secretary of Defense at the end of the Obama administration, remained in the position until Shanahan's confirmation. Shanahan was confirmed by the United States Senate with a vote of 92–7 on July 18, 2017, and became the 33rd Deputy Secretary of Defense on July 19, 2017.

In April 2016, he became senior vice president, Supply Chain & Operations, for Boeing. His responsibilities in that position included manufacturing operations and supplier management functions, carrying out advanced manufacturing technologies, and global supply chain strategies.

Shanahan served as vice president and general manager of Boeing Missile Defense Systems, starting in December 2004 overseeing the Ground-based Midcourse Defense system, Airborne Laser and Advanced Tactical Laser programs. He served as vice president and general manager of the Boeing 787 Dreamliner program, where he led the program during a period of the aircraft's development from 2007 to 2008. He next served as senior vice president of Airplane Programs at Boeing Commercial Airplanes, beginning in December 2008.

Shanahan joined Boeing in 1986, becoming involved in Computer Services and the Boeing 777 program. Over the course of his career, he held management roles with respect to the Boeing Missile Defense Systems, as well as 737, 747, 767, 777, and 787 commercial airline programs. He also played a role spearheading the recovery of Boeing's 787 program, and was known there as "Mr. Fix-it" from as early as 2008.

Patrick Michael Shanahan (born June 27, 1962) is a former United States federal government official who served as acting U.S. Secretary of Defense in 2019. President Donald Trump appointed Shanahan to the role after the resignation of Retired General James N. Mattis. Shanahan served as Deputy Secretary of Defense from 2017 to 2019. He previously spent 30 years at Boeing in a variety of roles.

Shanahan was born on June 27, 1962 in Palo Alto, California, the son of Jo-Anne Genevieve (née  David) and Michael George Shanahan. His father's original surname was "Rockholtz," and "Shanahan" is the surname of Patrick's step-grandfather. He grew up in Seattle, Washington, where he graduated from Bishop Blanchet High School in 1980. He attended the University of Washington where he earned a Bachelor of Science (B.S.) degree in mechanical engineering. He then earned a Master of Science (M.S.) degree in mechanical engineering from Massachusetts Institute of Technology, and a Master of Business Administration (MBA) from the MIT Sloan School of Management.