After what Herd described a 'rubbish' first half performance from his side - they turned things around against Dartford Whites to claim the Champion of Champions title.
It follows up their U19 Alliance League Cup triumph the previous season and their U19 Alliance Division C title win this time around.
Hertford were a goal down at the break but bagged a quickfire double through Joe Nardelli and Harry Pearson early in the second half.
Finley Sillince levelled things up for Dartford to send the game to penalties where stand-in Hertford stopper Dan Gee saved the Darts' sixth penalty - allowing Zen Cunningham with the chance to win it for Hertford.
"We had to learn to win a different way today," Herd said.
"Going down to ten men with 25 minutes to go was not easy but we showed good character, good courage and good work rate.
"We rode our luck a little bit at times but lady luck shone on us again today and what a fantastic achievement to go and become the best U19 team in the country at this level - it's a great accolade to have.
"We were rubbish in the first half. We couldn't settle, we looked nervous and jittery. We went under.
"I said to the boys at half time that we're better than that and to be fair, they came out second half and did really well in those first ten minutes."