It came five years after the fire at the west London residential block that claimed the lives of 72 people.
William and Kate laid flowers at the multi-faith service, organised by Grenfell United, a support group formed in the days after the fire by survivors and bereaved relatives.
A private meeting took place between the royal couple and those directly affected by the disaster, Kensington Palace said.
The service was live-streamed on screens positioned in the surrounding area so the wider community and public were able to watch.
Earlier, the names of the victims were read out at a separate service at Westminster Abbey.
There, the Very Rev Dr David Hoyle, Dean of Westminster, said the loss and anguish “are still vivid and sharp” as the congregation gathered “in sorrow and in pain”.
Marlene Anderson, the daughter of victim Raymond Bernard, also spoke during the emotional event at Westminster Abbey.
In the evening, firefighters from across the country formed a guard of honour as members of the community took part in a silent walk starting from the base of the tower.
Prime Minister Boris Johnson tweeted: “Today marks five years since the Grenfell Tower fire took the lives of 72 people.”
“My thoughts are with the survivors, those who lost loved ones and the wider community.”