In the build-up Daley said he had already achieved his gold medal.
Competing again at an Olympics, with his young family able to attend in support – unlike at the coronavirus-impacted Games of 2021 – was enough for him.
But still Daley departs, possibly for good this time, with an Olympic silver medal to add to his gold and three bronze medals.
He and Williams were almost faultless, only beaten by a pair who produced one of best Olympic performances of this Games.
After being tied with Canadian pair Rylan Wiens and Nathan Zsombor-Murray after the first two dives, the British duo edged ahead with their third.
There were huge roars in the arena after they scored 93.96 with their fourth. Any realistic hopes of gold faded when China responded with 95.88 from their next effort.
But that cannot take away the achievement of Daley and Williams, who ended with a huge score of 93.24 to raise the roof when 40 points fewer would have been enough for silver.
Daley made his comeback in December last year.
Before being officially selected for this team, he and Williams were barely able to train together with Daley living in Los Angeles.
Despite the hurdles, they finished the Olympic final with a score of 463.44, with China taking gold with a massive 490.35 and Canada bronze on 422.13.