Ryan McGuigan, 13, performed the skit at a Scotland Malawi Partnership event on Monday.
The pupil at St Margaret’s, Airdrie, said he had been doing impressions of the former First Minister since the independence referendum last year.
Receiving warm laughter from his captive audience, Ryan said in his impression: “I’ve heard the scaremongering accusations that the oil’s going to run out.
“It’s the most enormous resource in Europe and any other country would give their eye teeth to have command over these oil revenues.
“And I’ll tell Willie Rennie that it doesn’t keep me awake at night having to face the five Liberal Democrats, cause I’ll tell Willie Rennie this: See, because he joined up with the Tories, that’s why they’ve got five Liberal Democrats.”
MSP for Glasgow Humza Yousaf attended the event and tweeted a video of Ryan in action, commenting: “Met Ryan from St Margaret’s at Scot-Malawi event - he showed me his @AlexSalmond impression. I’d say he nailed it.”
Mr Salmond himself then retweeted the video and wrote: “This boy will go far! Absolutely fantastic!”
Speaking following his performance, the youngster said: “I started doing my Alex Salmond impression during the Referendum.
“I saw a clip of him tearing Willie Rennie to pieces and thought I’d give it a try, not that I’m a big Alex Salmond fan, mind you.
“I showed it first the my family and they thought it was really funny and I’ve been doing it since.”