Vesty, who is currently backs coach at Worcester Warriors, will join Boyd's management team at Franklin's Gardens this summer.
The new attack coach comes with a burgeoning reputation, having been skills coach on England's tour of Argentina last summer.
And Boyd, who spent the previous week assessing the situation at Saints as his current club, the Hurricanes, had the weekend off, is excited by the 36-year-old's coaching potential.
Saints players can show what they are made of during hectic start to season
NORTHANTS CRICKET LEAGUE: All your results and fixtures
Old and young players join for celebrations to mark 50 years of Barby Cricket Club
Ripley left frustrated as Steelbacks revert to bad habits in Lightning loss
Northampton Town boss Boothroyd gets on his bike for charity
"I didn't have a lot of knowledge about what was available up here and I did a lot of research about high potential, up-and-coming coaches," Boyd said.
"It's really important that you have a group of coaches that are open-minded, wanting to learn, wanting to grow and are enthusiastic.
"Most of all, you need people who are highly competent in their areas so they've got to have good knowledge.
"The players of today demand accurate knowledge and when I researched around, Sam's name kept coming up as a guy with a lot of credibility in the space he was in.
"I managed to connect with him and he was excited about the opportunity of coming here.
"We managed to get him across the line and it's a good signing for us."