Wallabies coach John Connolly claimed Mortlock's appointment as skipper was a direct result of the on-field leadership he demonstrated throughout the recent seven-Test campaign.
"Stirling embraced the captaincy role during the Tri-Nations and really led from the front with his performances on the field," Connolly said.
"He's a player that the other players enjoy playing with and his leadership has grown immensely during the season."
Wallabies selectors produced few surprises within the 30-man-squad with 14 of the players named boasting previous World Cup experience.
Veteran half-back Gregan is set for a record-breaking fourth consecutive World Cup campaign while Stephen Larkham and Chris Latham will both complete a hat-trick of World Cup appearances.
Undoubtedly the biggest surprise was the inclusion of 21-year-old Reds fly-half Berrick Barnes, who was named as Stephen Larkham's deputy for the tournament ahead of Waratahs counterpart Sam Norton-Knight.
And despite missing the entire domestic Test series following a shoulder reconstruction, Reds prop Greg Holmes was given the nod ahead of Benn Robinson and Rodney Blake.
Meanwhile, the selectors showed they were willing to gamble on the fitness of injured No. 8 pairing Wycliff Palu (shoulder) and David Lyons (Deep Vein Thrombosis) with both players named in the squad despite remaining in serious doubt.
The squad will kick-off preparations with the first of three Australian based training camps in Manly on July 31, ahead of their August 23 departure for a week-long training camp in Portugal.
The Wallabies will arrive at their World Cup training base in Montpellier on August 31 ahead of their first Pool B match against Japan, in Lyon on September 8.
Australia will also face Wales, Fiji and Canada during the group stage of the tournament.