Three penalties from Marc Sneyd gave the Black and Whites a 6-2 lead at the break in an error-strewn game, with Sam Williams slotting Wakefield's penalty.
Scott Grix gathered his own kick to score on his debut to give the hosts the lead in the second half.
But new boy Jake Connor collected Sneyd's kick with 12 minutes to go as the Challenge Cup holders won.
They finished third last season but were beaten in the play-off semi-final by eventual champions Wigan, and ground out an opening day win in difficult wet and muddy conditions at Belle Vue.
The loss is Wakefield's eighth in a row in the top flight as they lost all seven games during the Super 8s, after they finished eighth in Super League last season.
Albert Kelly and Josh Griffin also made their first appearances for Hull FC with Williams, Craig Huby and Kyle Wood making their Trinity debuts.
Wakefield head coach Chris Chester:
"I think both teams need commending as completion rates were up around the 75% mark and in those atrocious conditions, I think both teams need a round of applause.
"It was a tough game out there with two physical teams and two tries off kicks, there wasn't much between the two.
"We're obviously disappointed that we've conceded late on but we just need to be a little bit smarter."
Hull FC head coach Lee Radford told BBC Radio Humberside:
"I'm really, really pleased with how disciplined we were and stuck to what we were doing.
"We spoke about this performance all week due to the conditions and this time of year and the footy that you play, ultimately we made sure we had the patience to snag a try.
"One of Marc Sneyd's temptations is to chase the game and overplay but I thought he was patient and that's a really good sign for us."
Wakefield: Grix; Jones-Bishop, Lyne, Tupou, Johnstone; Miller, Williams; England, Finn, Huby, Ashurst, Kirmond, Sio.
Interchanges: Wood, Arona, Fifita, Walker.
Hull FC: Shaul; Fonua, Tuimavave, Griffin, Talanoa; Kelly, Sneyd; Taylor, Houghton, Watts, Manu, Minichiello, Ellis.
Interchanges: Connor, Green, Thompson, Washbrook.
Attendance: 7,027.
Referee: Chris Campbell.
Hull FC started their Super League season with a narrow win at Wakefield Trinity in a tight match.