Hillier shot a final-round 66 at The Belfry to lift his first DP World Tour title on a ten-under-par total of 278 and secure the first available place at Hoylake.
The New Zealander will make his second appearance in The Open after his debut at Royal St George’s two years ago.
He said: “It’s definitely a shock to the system. I’ve already got flights booked to the US for two events over there, so I’ll be changing my plans!
“[Qualification] wasn’t really on my mind today, I was quite a few back. I just happened to play some of the best golf of my life coming in, and that can change things.
“I played The Open at Royal St George’s and that was amazing. It was an experience I’ll never forget so I’m pretty excited to have another crack at it.”
Wilson and Wiebe finished joint runners-up on an eight-under-par total of 280 to claim the two remaining places.
Wilson’s last-gasp birdie on the 72nd hole means that the Englishman will tee it up for the seventh time in The Open and the first time since 2019 at Royal Portrush, while Wiebe will make his debut in golf’s original championship after a superb final round 66.
Wiebe said: “Everyone starts the week with goals in mind and that was certainly mine.
“[Royal Liverpool] is a special place with my family history, with it being the last major my dad [Mark] played in, in 2014, and this now will be my first.
“Sometimes it’s funny. You think you can’t write a really good script and then life gives you a proper script. It’s pretty incredible.
“It was a huge goal of mine, for sure. Obviously winning is always great but [qualifying for The Open] is a pretty big carrot for us.”
Wilson added: “When you haven’t been in them for while, you kind of tell yourself that it’s not a big deal. But when you get back in them it’s like ‘wow’.
“It’s awesome. This is where you want to be. They eyes of the world are on [The Open] and you want to be part of it.”
Meanwhile, a minimum 16 further places at The Open will be up for grabs when Final Qualifying takes place at Dundonald Links, Royal Cinque Ports, Royal Porthcawl and West Lancashire on Tuesday.
Fields of 72 players will compete over 36 holes as they seek the coveted prize of Open qualification.