Time to move on. That is the explanation Tony Fadell, a former star executive at Apple known for his aggressive management style, offers for his departure from Nest, a maker of digital versions of household staples like thermostats and smoke detectors that he helped found and sold to Google.

Alphabet, Google’s parent company, announced on Friday that Mr. Fadell was leaving Nest after leading it for six years, including the last two under the ownership of Google, which bought it for $3.2 billion in 2014. His departure comes after months of controversy regarding his leadership.

Mr. Fadell, the company said, will become an adviser to Alphabet and to its chief executive, Larry Page.

In a recent interview in his Palo Alto office, Mr. Fadell, 47, talked about his career. At Apple, he led the engineering team that created the iPod digital music player and worked on the first three versions of the iPhone. In 2010 he founded Nest with Matt Rogers, a young Apple engineer.