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.
7. Ilia Gruev - 7/10
Booked for a rash, late one but he was his usual busy, industrious self. A couple of nice moments going forward. | Getty Images
8. Willy Gnonto - 7/10
Central to Leeds' impressive start, involved in lots of good moments. Kept working hard. Kept getting caught offside. | Danny Lawson/PA Wire
9. Brenden Aaronson - 7/10
Tidy, buzzed around getting on the ball and linking play. Hassled and harried defenders. Photo: Lewis Storey
10. Manor Solomon - 7/10
Quiet spells, some rustiness but flashes of the danger he will pose and then definitive proof with that tremendous assist. Turned nothing into something with skill, pace and a cracking delivery. | LUFC
11. Mateo Joseph - 8/10
Took his goal brilliantly and deserved it. Worked hard. Ran the hard yards to defend, gave defenders problems when they had the ball. Led the line well. | Getty Images
12. Largie Ramazani - 7/10
A few glimpses of how sharp he can be in possession and didn't let Hull settle in possession. Straight into the action. | Getty Images