Single-leg amputee Peacock powered over the line in a season’s best 10.79 seconds and could not be separated from Johannes Floors.
Floors’ fellow German Felix Strang claimed T64 gold in 10.76 secs, with Costa Rican Sherman Isidro Guity Guity just a fraction of a second behind to secure silver.
The names of Strang and Guity Guity immediately flashed up on the scoreboard at the National Stadium in Tokyo but there was a lengthy, nail-biting delay to see who would complete the podium.
Peacock, who won gold in the T44 class in London and Rio initially looked to have earned the honour outright.
But Floors was eventually placed alongside him, with both athletes clocked precisely at 10.786 secs.
Peacock, 28, is back in the GB team for the first time since he won gold at the 2017 World Championships and his appearance on Strictly Come Dancing later that year.
He suffered a serious knee injury in 2019 and also had hamstring trouble ahead of travelling to the Far East, talking down his chances of another gold in the build-up the Games.
“One side of me is super happy that I was able to turn my season around and be competitive in that race,” he said.
“The other side of me, after I’d watched it back, was really annoyed. I was in a really good position at 60 metres. If you had asked me before the race for that, I would have said ‘no way I am taking that gold’.
“I have to give it to Felix, he was the best racer today. Guity Guity, wow, what a breakthrough to come into your first Paralympics and take a silver in one of the most competitive events in the sport.
“I’ve come back from a few injuries this year. Next year is going to be big. I know what I am capable of. All I can say is I’m really looking forward to next year, and Paris (Paralympics) is only three years away.”
Earlier, British wheelchair racer Andrew Small grabbed gold after blitzing his rivals in the men’s T33 100m final.
Small powered out of the blocks and claimed victory in a time of 17.73 seconds.
The blistering start proved crucial as defending champion Ahmad Almutairi of Kuwait threatened to snatch victory by closing the sizeable gap, only to cross the line a tenth of a second behind.
Small’s success was an upgrade on the bronze he won behind Almutairi at Rio 2016, with third place on the podium on this occasion going to his GB team-mate Harri Jenkins in a season’s best 18.55secs.
“I entered the race, I don’t ever expect outcomes, I just go and do it and see what happens and, hey ho, this is where we got,” the 28-year-old told Channel 4.
“I normally have a Garfield brought to me where ‘I hate Mondays’, so I may have to change that now.”
Victory for Small brought ParalympicsGB’s 24th gold of the Games.
Another Briton, James Freeman, finished fourth of the five racers in 19.69secs.
David Weir and GB team-mate Danny Sidbury each qualified for the final of the men’s T54 1500m, despite finishing fourth and sixth respectively in their heat.
Six-time Paralympic gold medallist Weir, who initially retired from track events following from a fruitless trip to Rio in 2016, crossed the line in 2:55.84, with Sidbury posting a personal best of 2:56.26.
However, both times were quicker than any of their rivals in the other qualifying race, guaranteeing places in Tuesday’s medal decider.