Ambassador Roos' tenure in Tokyo comes at an historic period in U.S.-Japan relations. Shortly after his arrival, power shifted from the Liberal Democratic Party (essentially the first time in 50 years) to the Democratic Party of Japan. Ambassador Roos played a key role in managing relationships through the transition.

On Aug. 6, 2010 Ambassador Roos became the first U.S. official ever to attend the commemoration ceremony of the atomic bombing in Hiroshima.

Prior to his appointment, Ambassador Roos served as CEO at Wilson Sonsini Goodrich & Rosati, a leading law firm in the US in the representation of technology, life sciences, and emerging growth companies. While there, he helped lead his firm during waves of innovation in Silicon Valley, from the growth of software and communications to the internet age and emergence of biotechnology, and further to today's focus on clean technology and renewable energy.

Ambassador Roos attended Stanford University and Stanford Law School.