Almost two months after Aneesh Chopra ended his tenure as the first US Chief Technology Officer, the position has been filled by Todd Park. Park, formerly CTO of the Department of Health and Human Services (HHS), got his start in health care technology. During his time at HHS, he worked on a series of "open data" projects that released datasets and allowed companies or hobbyists to do things like integrate government-collected hospital information into search results. He also led the HealthCare.gov initiative, which created a web tool for finding health insurance plans by zip code.
Like the position Park filled at HHS, the role of US CTO is only a few years old. Upon taking office, President Barack Obama created the Chief Technology Officer (informally the "technology czar") to "help modernize a Federal government relying too heavily on 20th century technology." There's not a great deal of information on what Chopra did with the role in his relatively short tenure, but it's supposed to be focused more on envisioning new ways to use technology than managing the current IT infrastructure. And unlike many elected officials, for whom technological ignorance is a point of pride, Park was specifically recruited by HHS for his ability to work with new technologies. If you're interested in reading up on Park's background, you can check out this Atlantic article from last year.