A “glad and humbled” Amla said he would give “all his heart” to the role, vowing to put together a “winning combination” able to return South Africa to the top of the Test rankings.
“Throughout the years I have concentrated mainly on my batting, trying to become the best batsman possible and hopefully I can still get there,” Amla said.
“But now I do feel it is time to act, to contribute in a team environment.”
Amla, 31, who made his test debut against India in Kolkata 10 years ago, praised the work done by his predecessor, whose legacy looms large.
“I have to pay tribute to Graeme and his leadership over the 10 years that I have been involved, there was certainly a lot of value that he added.”
Smith had captained South Africa in a world-record 109 Tests before announcing his retirement during the third and final Test against Australia last March.
Selectors said his replacement had been seen as a choice between three world class batsmen, Amla, AB de Villiers and Faf du Plessis.
But it was Amla, a devout muslim who has often shied away from the public eye, who won out.
Amla captained the South African team at the Under-19 World Cup in New Zealand in 2002 and was appointed captain of the Dolphins franchise early in his first-class career.
He resigned as captain after one season to concentrate on his batting.
Amla was appointed De Villiers’ vice-captain of the South African ODI team in 2011 and led the side in three matches, but gave up the job last year.
Amla was reappointed to that position on Tuesday.
Amla’s first assignment will be to lead South Africa in two Tests in Sri Lanka during July.
The 14-man Test squad for that tour was also announced Tuesday:
Alviro Petersen, Dean Elgar, Hashim Amla (captain), Faf du Plessis, AB de Villiers (wicketkeeper), JP Duminy, Stiaan van Zyl, Vernon Philander, Morne Morkel, Dale Steyn, Imran Tahir, Kyle Abbott, Quinton de Kock, Dane Piedt.
A one-day international squad was also announced:
Hashim Amla, Quinton de Kock (wicketkeeper), Jacques Kallis, AB de Villiers (captain), JP Duminy, David Miller, Wayne Parnell, Ryan McLaren, Dale Steyn, Morne Morkel, Imran Tahir, Vernon Philander, Faf du Plessis, Aaron Phangiso, Beuran Hendricks.