Takelo won 87 kilograms gold on the opening day of action at the Harvest Centre in Apia after defeating Josefa Otterberch of Fiji and then Fred Gwali of the Solomon Islands.
Tonga ended up the second-most successful country in taekwondo at Samoa 2019 with two gold and three bronze medals.
Taufatofua represented Tonga at Rio 2016, where he was also flag bearer, and he then made the shift to winter sports when he featured in cross-country skiing at Pyeongchang 2018.
The 35-year-old lent a hand during a three-week taekwondo training camp in Australian city Brisbane last month and also travelled to Samoa with the Tonga team.
Takelo told Radio New Zealand: "Pita has become a role model for all of them and watching him take his time to come and help is a great inspiration.
“So much thanks to Pita to take his time off to come and help.
“They have learned so much from this period and the mentality that Pita has shared with them.”
Prior to Takelo’s gold, his coach Paula Sitapa had been the last Tongan to triumph in taekwondo at the Pacific Games, in 2007.
Photo Getty Images. Caption: Rio 2016 flag bearer Pita Taufatofua