Helm passed away at age 71 on Thursday (April 19), a day after his family announced that the drummer was in "the final stages" of his battle with cancer.
Fellow Band star Robertson released a statement following Helm's death, in which he reflected on his long and complicated relationship with the drummer.
"Last week I was shocked and so saddened to hear that my old bandmate, Levon, was in the final stages of his battle with cancer. It hit me really hard because I thought he had beaten throat cancer and had no idea that he was this ill," he wrote. "I spoke with his family and made arrangements to go and see him."
Robertson's statement continued: "On Sunday I went to New York and visited him in the hospital. I sat with Levon for a good while, and thought of the incredible and beautiful times we had together. It was heartwarming to be greeted by his lovely daughter Amy, whom I have known since she was born. Amy's mother, Libby Titus, and her husband, Donald Fagen, were so kind to help walk me through this terrible time of sadness.
"My thoughts and prayers are with his wife Sandy. Levon is one of the most extraordinary talented people I've ever known and very much like an older brother to me. I am so grateful I got to see him one last time and will miss him and love him forever."
Garth Hudson, keyboardist and saxophonist for The Band, also remembered Helm in a post on his website.
Hudson said: "Levon Helm left us today at 1.30pm... I am terribly sad. Thank you for 50 years of friendship and music. Memories that live on with us. No more sorrows, no more troubles, no more pain.
"He went peacefully to that beautiful marvelous wonderful place. He was Buddy Rich's favourite rock drummer... and my friend. Levon, I'm proud of you."
The Band famously started their career as Ronnie 'The Hawk' Hawkins's backing band, before moving on to play with Bob Dylan in the 1960s.
Their 1968 debut album Music from Big Pink proved to be a landmark rock album. The LP ultimately ranked as #34 on Rolling Stone's 100 greatest records of all-time.
The Band went their separate ways following a 1976 concert, which Martin Scorsese documented for the acclaimed film The Last Waltz.
Helm would later regroup with Hudson, Rick Danko and Richard Manuel in the 1980s for a series of live tours.
The drummer also released his own solo albums, including the 2010 Grammy-winning Electric Dirt.
Helm is survived by his wife Sandy and daughter Amy.
Watch Levon Helm and John Hiatt perform 'The Weight' below: