Daniel Farke’s side started strongly, asserting their dominance over the Tigers but relinquished control as the first half wore on.
United went in goalless at the break but hit the front shortly after the restart thanks to a Manor Solomon assist for Joseph on the Tottenham Hotspur loanee’s debut.
There were also first appearances for new arrivals Largie Ramazani and Ao Tanaka, who were introduced from the bench, along with Piroe who took receipt of Junior Firpo’s pinpoint cross-field ball before slotting beyong Hull goalkeeper Ivan Pandur to put the result beyond doubt.
Here are the player ratings as Leeds move up to fourth in the Championship table.
1. Illan Meslier - 6/10
A couple of vital stops and a couple of poor moments, either of indecision or risky and careless distribution. Photo: Stu Forster
2. Jayden Bogle - 6/10
Faced a difficult battle up against Millar and came off second best at times but dug in and won a share of the battles. Photo: Gary Oakley
3. Joe Rodon - 6/10
Struggled at times in a tricky battle with Bedia. Wasn't always helped by the officiating but there were a few shaky moments. | Getty Images
4. Pascal Struijk - 7/10
Solid, passed it well. Held a threat from set-pieces even if he couldn't find a finish. Photo: Richard Sellers
5. Junior Firpo - 8/10
Solid, good in the air as per usual, aggressive in the tackle and got forward well. Won the ball back and claimed a lovely assist for the second. Photo: Stu Forster
6. Ethan Ampadu - 7/10
Steady. There was some nice passing. When Leeds had control he was key to it. | Getty Images