"To know Garry Marshall was to love him," the Oscar winner told People. "And I was luckier than most to have loved him for my entire adult life and luckier still to have been loved by him because his love was unconditional, inexhaustible and magical."
The filmmaker, who passed away July 19 at the age of 81 of complications from pneumonia following a stroke, helped launch Roberts's career when he cast her in 1990s Pretty Woman.
"The map of Garry's career is long and illustrious. Innovative and simply amazing," she continued. "I was 7 years old when Happy Days came on TV. Followed a couple of years later by Laverne & Shirley and then Mork & Mindy. I have said before that Garry Marshall raised me, and it is rather true."
"For 10 years he made all who watched television laugh and learn and strive to be better, more open people. He taught us to be nice, that life could be simple and sweet and, most importantly, that friends and family were everything."
"It is my great fortune that there were only a few short years between Happy Days going off the air and Garry Marshall walking into my life and changing it in so many ways," she added. "His family was everything to him, and it showed in every piece of work he ever did."
Prior to his death, Roberts gushed about the filmmaker to InStyle, saying, "He was really a great shepherd for me in the beginning. You can never give credit for anything to one person. Singular credit just doesn't exist. But if I were to single someone out as a person whom I feel very indebted to, in what I realized the other day is my 30-year career, it would be Garry."
"He knows how to touch all those places in our hearts that we just sit around longing for people to tap into," she continued. "He's a master of that."