Federighi returned to Apple in 2009, hired to lead macOS engineering[7] at a time when Apple had just finished developing Mac OS X Snow Leopard, which was highly regarded for its focus on quality.[8] In March 2011, Federighi succeeded Bertrand Serlet as vice president of Mac Software Engineering at Apple,[9] and in August 2012 he was promoted to senior vice president, reporting to CEO Tim Cook.[4] Upon Scott Forstall's departure from Apple, his role was expanded to encompass iOS in addition to macOS.[10]