Adams, who turned 26 on Wednesday, added a Games record for good measure with a throw of 20.47m. It came on her first attempt of the night at Jawaharlal Nehru Stadium, and she celebrated with a jump of joy.
In fact, she broke her own mark of 19.66m set in Melbourne four years ago with all six of her throws, each of which went over 20m.
Adams, the Olympic and world champion, had been the hot favourite going into the event, being the only one of the 12 competitors to have gone over 20m.
The gold is the second for New Zealand in New Delhi, after track cyclist Alison Shanks' victory in the 3000m individual pursuit yesterday.
It is Adams' third Commonwealth medal. The first was a silver in Manchester in 2002 as a 17-year-old, and the Aucklander has also added the world and Olympic titles to her resume since then.
The 12-strong field that assembled at Jawaharlal Nehru Stadium might not have been the strongest that Adams has come up against, but that didn't diminish her delight at her win.
"Every time you put the bib on in competition, it's a matter of doing what you have to do," she said.
"People just expect you to win, so to come out here and defend my title and defend it with a very big throw, I'm bloody happy."
Silver went to Cleopatra Brown of Trinidad and Tobago with 19.03m, while Samoa's Tasele Satupai took bronze with a personal best of 16.43m
Adams was short of her own personal best of 21.07m, achieved in winning the world athletics final in Greece last year, but her consistency was a feature of her latest victory.
"I'm stoked with my consistency throughout the series," she said.
"It's the end of the season, I'm tired, breaking the Commonwealth record - I cannot ask for much more really."
Adams has been working on technical changes with new coach Didier Poppe since parting ways with long-time mentor Kirsten Hellier earlier this year.
She said she was seeing the benefits of those changes.
"Things take time," she said. "It's a matter of just keeping going until we get there."
