Second rows Bakkies Botha, Victor Matfield and Danie Rossouw, flanker Schalk Burger and centre Jaque Fourie will join Smit in playing in their third Rugby World Cup, a contrast to 20-year-old fly half cum full back Patrick Lambie who is the youngest member of the squad.
"The squad has a backbone of proven title-winning ability and experience as well as a strong component of new stars," said coach Peter de Villiers.
"Injury has denied us one or two players who could have been very important to us, but I am very happy with the squad we have picked.
"This squad has the experience and ability to make a strong challenge of the title, but we know it will be very difficult. It has been a tough season to date and we have had some challenges with the amount of rugby the players have had to play."
With an average of 40 caps per player, South Africa have had a mixed year so far, a weakened side suffering heavy losses to Australia and New Zealand away in the Tri Nations and were in danger of arriving at RWC 2011 without a win before beating an All Blacks side missing many of its stars 18-5 last weekend.
South Africa will have to hit the ground running at RWC 2011 with Wales their opening Pool D opponents at the Wellington Regional Stadium on 11 September.
Fiji, the side they beat in the 2007 quarter-finals, Namibia and Samoa then await the Springboks.
South Africa squad for RWC 2011
Gio Aplon, Juan de Jongh, Jean de Villiers, Fourie du Preez, Jaque Fourie, Bryan Habana, Francois Hougaard, Butch James, Pat Lambie, Odwa Ndungane, Ruan Pienaar, JP Pietersen, Frans Steyn, Morné Steyn.
Willem Alberts, Bakkies Botha, Heinrich Brüssow, Schalk Burger, Bismarck du Plessis, Jannie du Plessis, Francois Louw, Victor Matfield, Tendai Mtawarira, Johann Muller, Chiliboy Ralepelle, Danie Rossouw, John Smit (captain), Pierre Spies, Gurthrö Steenkamp, CJ van der Linde