Three years ago the club had one of the game's greatest ever players in skipper Cameron Smith, New Zealand hooker Brandon Smith and a young Grant on the books.
Rarely in the history of rugby league has a team been blessed with such riches in the No.9, so much so that Grant was loaned out to Wests Tigers in 2020 to get some NRL experience.
Now he is flying solo as the undisputed number one Storm hooker after Cameron Smith retired at the end of 2020 and Brandon Smith joined the Sydney Roosters at the completion of last season.
The Storm mixed it up with how they used Grant and Brandon Smith.
Grant, 24, would start and Smith would come off the bench, or vice-versa. Often they would spend plenty of time on the park at the same time with Smith in the middle forward role and Grant at dummy-half.
"The last two years we were blessed to have two of the best number nines in the game in the same team … and when they were both on the field they were a terrific duo that worked so well together," Storm general manager of football Frank Ponissi told AAP.
"We were fortunate that Brandon could play in the middle.
"No doubt we will miss that combination of Harry and Brandon together but we are excited to see what else Harry can do without Brandon.
"Harry, like everyone else, will evolve his game this year ... I am sure he will add an extra string to his bow."
Grant has played 52 NRL games, five State of Origins for Queensland and been part of two series wins. Throw in his five games for Australia and a World Cup final victory and it is a remarkable strike-rate in rep footy for someone in the formative stages of his career.
"It is quite an achievement and I am excited to think what is on the horizon," Ponissi said.
Grant's Storm teammates now have a better grasp of how he plays, with his electrifying speed out of dummy-half a real strength.
Cameron Smith was the master of guile and controlling the pace of a game, areas Grant will no doubt look to improve.
"One of Harry's great strengths is his ability to get out of dummy-half and when he came back from the Tigers it took our players a bit to adjust to that after Cameron had played at a different speed," Ponissi said.
"Even though he is at a high level now he'd be the first to admit there are many areas he wants to get better. He is coming off a very good base."
