"I am saddened by the passing of my friend Malcolm Young, I can't believe he's gone. We had such great times on the road," Johnson wrote on his website. "I was always aware that he was a genius on guitar, his riffs have become legend, as has he."
Johnson continued, "He has left a legacy that I don't think many can match. He never liked the celebrity side of fame, he was too humble for that. He was the man who created AC/DC because he said 'there was no Rock n' Roll' out there."
Johnson joined AC/DC in March 1980, seven years after Malcolm and Angus Young formed the band and a month after singer Bon Scott's death. Johnson remained a member of AC/DC from 1980's Back in Black through 2014's Rock or Bust.
In recent years, both Johnson and Malcolm Young had been forced into premature retirement due to health issues; Johnson was struck by a potentially deafening ear problem, while Young suffered from dementia prior to recording Rock or Bust. Longtime bassist Cliff Williams also retired from the band following the Rock or Bust Tour.
In an interview following Young's diagnosis, Johnson said of their rhythm guitarist, "He was the one that was behind AC/DC. He was our spiritual leader. He was our spitfire."
"I am proud to have known him and call him a friend, and I’m going to miss him so much," Johnson added Monday following Young's death. "I salute you, Malcolm Young."