Now his successor has honoured him in a new video as part of the Omaze charity campaign, which aims to raise funds for a children's research hospital in the US.
In the clip, Zachary says: "It was an honour and a privilege to know him and to call him a friend.
"Leonard's love for the human spirit shone through every thing he did. He touched lives around the world, and he is greatly missed."
The video follows a poignant photo tweeted by astronaut Terry Virts earlier this year, who paid his respects from the International Space Station.
The stunning shot sees the astronaut displaying the Vulcan salute - one of the trademarks of Nimoy's Star Trek character, Mr Spock - with Earth in the background.
Watch the ‘Star Trek’ cast’s video tribute to Leonard Nimoy above.