Hunter’s side defeated Ireland 34-7 in a title decider in Dublin on Friday night, giving the visitors their first clearn sweep in the Women’s Six Nations since 2012.
The victory capped an amazing period of success for Hunter, who was recently awarded an MBE for services to rugby and won the 2016 Women’s Player of the Year title.
England are in the same World Cup pool as USA, Spain and Italy and Hunter said: “I am excited to see how we can push on from here.
"That desire among the team to get better and better has meant we have grown as a squad and the management team deserve a lot of credit.
“We have worked for five long years to get that Grand Slam. We fell short last year and we learned a lot about ourselves and this year we have learned to stick with the process and trust in each other.”
England also won the Under-20 Grand Slam, beating Ireland 14-10.