Wakefield Trinity rose from promotion last season to claim their first Super League title, beating Warrington 23-10 on Saturday.
The Wildcats finished fourth in the regular season, then defeated Leigh Leopards 26-16 and favourites Wigan Warriors 33-6 to reach their first grand final.
They led 19-0 at halftime before a sold-out crowd of 71,728 at Old Trafford.
Isaiah Vagana scored in the 25th minute, and former NZ Warriors teammate Jazz Tevaga crossed from dummy half in the 35th.
Warrington fought back after the break, but Wakefield scored a fourth try midway through the second half to secure victory.
The win gave Wakefield its first major trophy since the 1960s, when the club competed in the former first division.
Vagana's title was a family milestone: his father, Warriors great Joe Vagana, won grand finals with Bradford Bulls in 2001, 2003 and 2005.
Former Warriors halfback Mason Lino was also in the Wakefield squad, while Auckland-born Caleb Hamlin-Uele and Christchurch-born Caius Faatili were interchange players.
The result also delighted former Warriors who had represented Wakefield, and Roger Tuivasa-Sheck, who will join the Wildcats next year.