Megan Smith, a Google vice president and champion of women in technology, has been named the new chief technology officer of the US. Smith is an MIT-educated engineer who worked most recently at Google X, the company's lab for hyper-ambitious projects like the self-driving car and the future of robots. Before that, she led the business development team for nine years.

Alex Macgillivray, Twitter's former top lawyer, has been named deputy CTO. It's an interesting choice: at Twitter, Macgillivray set a tone for that company's independence from the US government and resistance to law enforcement data requests.

Smith is only the third US CTO ever

The US CTO position is relatively new. The first US CTO, Aneesh Chopra, served from 2009 to 2012. He was succeeded by Todd Park, who left in late August. Smith will be the third US CTO ever.

The role is loosely defined as an advisor on technology policy. "Smith will guide the Administration's information-technology policy and initiatives, continuing the work of her predecessors to accelerate attainment of the benefits of advanced information and communications technologies across every sector of the economy and aspect of human well-being," writes presidential science advisor John Holdren, according to The Washington Post.

The previous US CTO, Todd Park, has been moved to an advisory position based in Silicon Valley. Park was responsible for launching the much-lauded Presidential Innovation Fellows program, which brings young tech talent to the White House for two year stints, and helping to coordinate repairs to the technical side of Healthcare.gov.

The appointments of Smith and Macgillivray, both hard-hitters from two major Silicon Valley companies, shows the White House is taking this role seriously. The position is so new, however, that Smith and Macgillivray have the opportunity to define what the US CTO should be.