The ISPS HANDA Australian Open was the second event in the Open Qualifying Series, which offers players opportunities around the world to qualify for golf’s oldest Major Championship.
Niemann defeated Hoshino on the second hole of a sudden death play-off to win after the pair finished regulation play tied on 14 under.
The co-sanctioned DP World Tour and Challenger PGA TOUR of Australasia event was played at The Australian and The Lakes, with the former the sole host over the weekend.
Niemann will feature in The Open for a fifth time with his best finish coming in 2022 at The 150th Open where he finished tied 53rd at St Andrews.
Thanks to Hoshino's runner-up finish in Sydney - his second in as many weeks in Australia - the 27-year-old will compete in The Open for a fourth consecutive time after making his debut in 2021.
"Very grateful. [I hope] to be up on the leaderboard in The Open next year," said the Japanese in the immediate aftermath of narrowly missing out on his first DP World Tour title.
With Min Woo Lee, who is already qualified for The 152nd Open, in outright third at his national open, the third and final qualifying spot in the field at Royal Troon went to Major champion Adam Scott after his final round 68.
The Australian Masters winner finished in a tie for fourth on home soil alongside Grant Forrest and Laurie Canter but secures his place due to his higher standing in the Official World Golf Ranking.
This will be his 24th consecutive appearance since making his debut at The Open at St Andrews in 2000.
The 152nd Open will be played at Royal Troon from July 14-21 2024.