"If you know Jared, he's a very calm, stable voice," Haley told MSNBC.
The Indian-American envoy's defence of Kushner, 36, came after the American media reported last week that he discussed to open a secret "back-channel" between Russia and Trump's presidential transition team in a meeting with the Russian ambassador to the US, Sergey Kislyak, last December.
"There is not a lot that rattles him. So I suspect that he'll continue doing his work like he always has. He's said that he will totally comply with the investigation and give every ounce of information that they need. And I think we can expect that," Haley said in response to a question.
"Well, I haven't talked to him since all of this came out," Haley said.
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The White House too has defended the role of Kushner, who is married to Ivanka Trump.
"I would just say that Kushner's attorney has said that Kushner has volunteered to share with Congress what he knows about these meetings, and he will do the same if he's contacted and connected with any other inquiry," White House Press Secretary Sean Spicer told reporters.
Yesterday Politico reported that Kushner is back in the West Wing and continuing to lead meetings despite the rising tide of Russia-related questions.