The 25-year-old has earned 76 caps for the Stormers since making his debut in 2012 and will be ably assisted by his good friend and fellow Springbok Etzebeth.
Both players have walked a long road together within the structures of Western Province Rugby since attending the Western Province Rugby Institute in 2010, along with the likes of Frans Malherbe, Nizaam Carr and Siyabonga Ntubeni who are all still their teammates.
Stormers head coach Robbie Fleck said that Kolisi will be well supported by a strong core of senior players within the squad as they tackle a demanding 2017 Super Rugby campaign.
"We have developed a number of strong leaders in this group, so Siya [Kolisi] will certainly not be shouldering the responsibility on his own, but we felt it important to appoint someone who the team can rally around.
"Although still quite young, Siya is already an experienced player who has matured both on and off the field and is one of the most popular and respected players in our squad," he said.
Kolisi said that it is an honour to be asked to captain the Stormers, which is a responsibility that he does not take lightly.
"There have been some great players who have led the Stormers out at Newlands, so for me to be amongst them is both a great privilege and a great responsibility.
"With the support of Eben and the rest of the senior players in the squad I am confident that we can create something special that our fans can be proud of," he said.
Etzebeth said that having played alongside Kolisi in a Stormers jersey for five seasons, he is looking forward to the new challenge that lies ahead of them.
"Siya and I have played together for a long time and I am honoured to stand beside him as we look to take the Stormers to the next level," he said.
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