The three-time grand slam champion is playing in his final Wimbledon and was honoured at a ceremony on Centre Court on Thursday evening.
Murray and Williams played mixed doubles together at the All England Club in 2019, while the American also referenced Murray's famously grumpy on-court demeanour.
"Congratulations to you Andy Murray for such an incredible career," said Williams in a video on the social media platform X.
"I have to say I've always enjoyed watching you. One of the main reasons because you were one of the few players who would be more angry than me on the court, which is a hard thing to do. May have been an attitude just like mine let's say.
"But to me it was the most exciting thing to watch and I had the pleasure of playing mixed doubles by your side, which was such a fantastic experience to do that, at Wimbledon nonetheless. It really was one of the highlights of my life.
"I'm just so grateful that I had that experience and I also hold a special place in my heart to you because you always speak out so much for women and everything that women deserve."
Included in the video montage played on Centre Court was Murray correcting a reporter who overlooked the achievements of American female players during a press conference in 2017.
Murray broke new ground by hiring Amelie Mauresmo as his coach in 2014, while he frequently highlights the women's game.
"You were the leader in that and the things you said about myself and Venus, so many things about how we were always so inspiring and what we meant to you, it really went such a long way in my heart," added Williams.
"I will always be grateful for that, I will always be grateful for the support you gave myself, the support you gave women and the excitement that you brought and bring to tennis.
"Watching you win Wimbledon and the US Open and those gold medals was so exciting. I truly enjoyed it. I've always been such a fan, as you already know, and I will always be cheering for you and rooting you on in whatever you decide to do next."
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