One of last season's relegated Premier League sides were facing defeat when Josh Bowler and Ike Ugbo gave Cardiff a 2-0 advantage at half time.
However, a Liam Cooper header and a last-gasp Crysencio Summerville strike earned Leeds a deserved share of the spoils.
On their return to second-tier football, Leeds had the better of the opening quarter, but Wilfried Gnonto, deputising down the centre of the attack, was wasteful on two occasions.
The Yorkshire giants were soon made to pay as Cardiff took the lead on 26 minutes, Bowler converting from close range after his initial effort had been blocked by a Leeds defender.
Pressure continued to come from Leeds, Crysencio Summerville forcing a save out of Jak Alnwick, yet Daniel Farke's side soon found themselves two goals down as Ugbo finished from inside the six-yard box after Aaron Ramsey had seen a goalbound effort blocked.
To Leeds' credit, they picked up where they left foot after the restart, and Cooper delivered the goal that their play deserved with a powerful header from no more than eight yards out, albeit injuring himself in the process and needing to be substituted.
While Ugbo could have restored Cardiff's two-goal lead instead of flashing a shot off target, the majority of the opportunities were going to Leeds, with Gnonto seeing a shot turned onto the crossbar and Daniel James having a low strike kept out by Alnwick.
Cardiff made a triple substitution with 13 minutes remaining to inject some energy into their side, the Welsh side sitting deeper and deeper as Leeds' maintained a high-octane pace.
That decision appeared to have worked until Summerville broke Cardiff's resistance in the fifth minute of added-on time, the winger reacting fastest to a shot being blocked on the edge of the area to coolly sweep a low effort into the bottom corner from 15 yards out.