Palmer, who won seven Majors during his illustrious career, died aged 87 in Pittsburgh last month due to complications of heart problems.
Leading players from past and present were at the service today, and arguably the greatest of them all - 18-time Major winner Nicklaus - hailed Palmer as "the king" of golf.
"Arnold came along when golf needed him most. When TV first embraced the sport of golf, it had a swashbuckling hero in Arnold as the game's face. He was the everyday man's hero, and played a game we could all appreciate and appealed to everyone," he said during his speech.
"If there was ever a problem, I knew Arnold had my back and I had his... I may have had to battle 'Arnold's Army' early on, but I never had to battle Arnold Palmer... He was 'The King' of our sport, and he always will be. Today I hurt just like you hurt. You don't lose a friend of almost 60 years and not feel an enormous loss, but my wife often says 'memories are the cushions of life'.
"Each of you sitting here today, or perhaps at home, has at least one wonderful memory of Arnold Palmer to balance out your hurting heart.... so for today and many years from now, I simply ask you to just remember when... Arnold Palmer touched your life, touched your heart and please, don't forget why."