However, he urged the supreme leader to no work to defuse international tensions over Pyongyang's controversial nuclear programme.
Mr Putin's comments come after Kim unexpectedly agreed to restore talks with neighbouring South Korea two years after relations broke down.
"I believe Mr Kim Jong-un has won this round," Putin told Russian journalists.
"He has achieved his strategic task – he has a nuclear warhead, and a global-range missile with a range of up to 13,000 kilometres (8,000 miles), which can now reach practically any point of the globe, at any rate any point on the territory of its potential enemy.
"He is an absolutely competent and already mature politician."
The Russian leader added it was now in Kim's interest to "harmonise the situation".
Next month's Winter Olympics in Pyeongchang faced been overshadowed by mounting tensions, with the North repeatedly test-firing missiles it claims are capable of reaching the US mainland.
But Pyongyang – which boycotted the 1988 Summer Olympics in Seoul – agreed on Tuesday to send athletes to the Games during formal talks at Panmunjom in the Demilitarised Zone.
The White House has said that Trump is open to the US holding talks with North Korea "under the right circumstances."
The comments to The Journal echoed remarks Trump made to reporters over the weekend at Camp David, in which the president said that dialogue with Pyongyang was not impossible.
https://twitter.com/intent/tweet?url=https%3A%2F%2Fwww.thesun.co.uk%2Fnews%2F5325249%2Fvladimir-putin-says-shrewd-and-mature-kim-has-won-this-round-with-donald-trump-in-row-over-nuke-tests%2F&text=” target=”_blank” title=”Click to share on Twitter