John Giannandrea, senior vice president of engineering at Google and one of the company’s leading public voices on artificial intelligence issues, is stepping down from his position as head of the search and AI units, according to a person with knowledge of the change. A Google spokeswoman confirmed the move in an email.

The move comes two years after Mr. Giannandrea’s role expanded following the departure of former search chief Amit Singhal. Google is reorganizing its AI responsibilities at a time of a companywide push to improve search, sell more mobile devices and persuade more large companies to use its cloud-based AI services. Google CEO Sundar Pichai has said infusing Google products with AI can make them more competitive.