Indeed, many Tigers fans may well have Googled his name to see just who exactly was heading their way from NRL outfit Canterbury Bulldogs.
However, the Australian prop, who has signed on again with the West Yorkshire club until 2020, must surely be one of the best-value overseas recruits in the summer era.
Undoubtedly, Millington has gone on to become one of the most integral, consistent and well-respected parts of Daryl Powell’s squad who, of course, won the League Leaders’ Shield for the first time in the club’s 91-year history last week.
A ball-handling prop who brings such enterprise to an already enterprising side – Millington effortlessly filled in as a stand-off last term – Millington is similarly an excellent defender in the middle and one of the side’s vocal leaders.
He was already contracted for 2018 but has now extended it further. Sydney-born Millington, 30, said: “It’s something we’ve been talking about for a little while and the club’s been fantastic in helping us out.
“There was a few things we had to sort out off the field for me to be able to stay here and this has made it possible. We’d like to thank them for that; they’ve been fantastic.
“But we love it here. It’s the only club I’ve played for in this country. This is home for us. It is fantastic.”
He will be 34 when this deal expires so, realistically, the ex-Cronulla Sharks forward could finish his career at Tigers.
“I’ve said before that I don’t think I’d be able to play for another club so this will be the only club that I stay at until I go home,” he added.
“It was a totally different club when I started here. The club’s transformed off the pitch and on it and I’m proud to be a part of how that’s happened.”
Castleford finished 13th, 12th and 12th again in Millington’s first three years at the club and almost went into administration before Powell helped turn around their fortunes. He said: “He’s one of the reasons why we have the ability to sign superstar type of players now.
“People understand that he’s a coach who can get the best out of you; I think you’ll get people who are on the cusp of England honours that recognise if they come here he can develop them into where they want to get to.
“Look at Paul McShane. He’s been fantastic since he arrived and hopefully he gets to go on his little trip at the end of the year for the World Cup. Personally, Powelly’s been a great coach; the way he likes to play the game really suits me.”
Millington has scored 24 tries in 152 games for Castleford who are now seeking to go on and win a first-ever league title.
Powell said: “Grant’s been outstanding again this season and I’m delighted he’s extended.
“His skill sets are second to none as a front-row and he’s been integral in the way we’ve played the last few years. I’m confident he’ll continue to improve and drive standards.”