The 18-year-old Olympic bronze medallist won the gold following a tense final in which he scored 542.15 to take victory from a four-man field.
Overcoming sluggish efforts in his opening two dives, Daley held his nerve to receive two straight 10s to roars from a delighted crowd.
“It’s great for where I am right now in my training cycle and the whole four-year cycle,” said Daley.
“To be scoring so high at this stage in the game isn’t quite surprising because I knew I could do it but it does come as quite a nice reward for all the hard work I’ve been putting in.
“I haven’t necessarily been seeing the rewards in training recently so to come here and dive well gives you that extra boost.
Russia's Victor Minibaev, who came fourth at the Olympics, finished second, just 4.55 points behind Daley.
He closed to within 10 points of the Brit going into the final round of dives, and didn’t give up the contest lightly.
“It was quite a close competition from the word go really. I missed my first two dives which was quite frustrating but I had to have the right mindset to keep going and believe anything could happen.
“Victor is an incredible diver – when he’s diving well, he dives very well. I knew I had to get 10s to stay in the competition and I just held that attitude for my last four dives.”
Fellow Brit and Olympic finalist Couch finished fourth in the women’s platform with 350.45.
China’s 14-year-old world junior champion Si Yajie won out with a score of 405.60, ahead of 15-year-old compatriot Liu Huixia (374.40) and Mexico’s Alejandra Orozco (367.45).
“I am really pleased with my performance tonight,” said Couch. “Fourth is a horrible place to come but I have never medalled at a World Series before so I am really pleased.
“I didn’t expect to score over 350 in this competition. I scored 360 at nationals in Plymouth a few months ago but coming into this international and getting 350, I am really happy.
“I have a lot more to prove, I am going reflect upon this score today and continue to work on my dives back home.”
Couch also just missed out on a podium place in the opening day’s 10m Synchro, finishing fourth.