The comedian and food critic, who originally trained as a lawyer, said he was "stoked" to transition into current affairs.
"Being on every night really gives you an opportunity to build a relationship with your audience and workmates - it's a cool and unique opportunity, and I'm stoked to be on the team."
Mau worked on TVNZ's Breakfast before taking over a presenting role on Fair Go in recent years.
She will leave that role to take up her new post at Seven Sharp, she said.
"I'm really looking forward to working alongside Greg and Jesse in the studio, both of whom bring a wicked sense of humour and depth of knowledge to the show."
Boyed has spent a decade at TVNZ, with recent roles on ONE News at 6, Tonight and Q+A.
Seven Sharp is due to air in a few weeks.
Announcements on who will replace Ali Mau on Fair Go and Greg Boyed on Tonight will be made in the coming weeks, TVNZ said.
- Herald Online