Page's duties will be taken on by Sundar Pichai, currently CEO of Alphabet's Google unit.
Page and co-founder Sergey Brin said in a letter released by the company that "We've never been ones to hold on to management roles when we think there's a better way to run the company. And Alphabet and Google no longer need two CEOs and a President. Going forward, Sundar will be the CEO of both Google and Alphabet. He will be the executive responsible and accountable for leading Google, and managing Alphabet's investment in our portfolio of Other Bets."
Pichai joined Google in 2004 and helped develop the Chrome web browser.
Page and Brin will remain on Alphabet's board of directors.
Shares of Alphabet rose $8.40, or 0.65%, to $1,303.68 in after-hours trading.
Alphabet is a holding in Jim Cramer's Action Alerts PLUS member club.