The pressure continues to mount on John Aloisi after the Heart coach watched his side succumb to a brilliant display by the former Perth striker.
After a scrappy opening half-hour, Newcastle broke the deadlock with a superb volley on the edge of the area from the Jets striker.
The impressive youngster doubled the Jets lead with a superbly taken goal in the 55th minute before the Heart got one back through a deflected free kick from Andrea Migliorini shortly after.
But the Jets sealed the points midway through the second half with Taggart completing his treble.
The match started in perfect conditions but both teams struggled to maintain possession in the early stages.
The Heart had the first real chance when a dangerous free kick from Iain Ramsay fell to David Williams inside the six-yard box, but he fired his volley straight at Jets goal keeper Mark Birighitti who made a smart reflex save.
The Jets got their first opportunity through captain Ruben Zadkovich in the 12th minute, when his in-swinging free kick from the touchline evaded everyone forcing a spectacular save from Andrew Redmayne.
The Heart had the better of much of the first half but could not translate their dominance into a goal, while the Jets picked up four yellow cards for some cynical defending in the opening stanza.
The Jets hit the lead in the 38th minute through a lovely piece of improvisation from Taggart.
After struggling to control a pass from Zadkovich on the edge of the area, the ball sat up nicely for Taggart who smashed a volley past the helpless Redmayne, sending the Hunter Stadium crowd into raptures.
A melee broke out moments later when Heart players reacted to a late challenge from Taggart who picked up a yellow card, along with Zadkovich for his involvement in a fracas with the Heart players.
The Jets should have doubled their lead on the stroke of half-time when Nathan Burns found Zadkovich with a lovely ball inside the area but the Jets skipper blasted his shot over the bar with the goal at his mercy.
The Jets introduced Emile Heskey in the 51st minute and the Jets nearly scored moments later when an incisive run from Burns opened up the Heart defence but his drive was well saved by Redmayne.
The Jets doubled their advantage in the 55th minute after Taggart scored his second of the match.
The in-form striker was well found on the edge of the area by Jacob Pepper and he expertly curled his shot into the bottom right corner of the goal leaving Redmayne with no chance.
The Heart hit back in the 58th minute through a Migliorini free kick, which took a huge deflection off Jets defender Josh Mitchell.
But the Heart's joy was short lived as Taggart scored a third, completing his first hat-trick in the A-League.
The 20 year-old found himself in acres of space on the edge of the area and he calmly slotted his shot into the bottom left corner, leaving Redmayne to question his team's defending.
Taggart limped off with an injury in the 81st minute but received a rousing reception from an appreciative home crowd.
The Jets finished the match by far the stronger and could have easily extended their advantage but they had done enough to ensure their third win on the trot.
Newcastle Jets 3 (Taggart 38, 55, 62)
Melbourne Heart 1 (Migliorini 58)
Crowd: 12,806 at Hunter Stadium