Sir Jonathan Ive promised iOS7 would take the company in an "important new direction" as he showcased the system at Apple's annual World Wide Developers Conference in San Francisco. The new operating system - which has a cleaner look - was showcased in a short video accompanied by an explanation from its London-born designer.
Sir Jonathan, known as Jony, said: "We see iOS7 as defining an important new direction and in many ways a beginning." His words followed a rousing speech from Apple's chief executive Tim Cook whose bold performance was picked up by industry experts as an indication of Apple's confidence.
iOS7 - described by Mr Cook as "the biggest change to iOS since the introduction of the iPhone" - arrives just months after Apple posted its first profit slide in a decade and follows tough scrutiny of the firm's tax arrangements on both sides of the Atlantic. The iOS 7 will be available in the autumn, Apple said.
It was announced as Apple revealed changes to its desktop and laptop computers - including all-day battery life for the MacBook Air - and issued a defiant response to those who have suggested the company could lose its crown as a leading innovator.
Industry observers appeared largely convinced and suggested the announcement would go some way to silencing Apple's critics. The new software has been designed to make the iPhone appear bigger, with features crafted to take advantage of the entire screen.
Text is said to appear sharper while a "control centre" on the phone allows users to adjust settings with just one swipe from the bottom of the screen. This gives instant access to functions such as Airplane Mode, Wi-Fi, Bluetooth or Do Not Disturb, and enables users to quickly pause or play a song, jump to the next track and stream music.
Meanwhile a "notification centre" will now be available from the "lock" screen so users can view updates with a "simple swipe". Apple has also introduced an AirDrop tool to share content - which is said to be fully encrypted - with contacts nearby, and has added further updates to its cameras and Siri.
Apple has also given developers a preview of OS X Mavericks - an update to its computer operating system - with more than 200 new features.