Malky Mackay admitted he needed to give his Cardiff side a few harsh words at half-time in order to overcome Leeds.
Craig Bellamy curled home a superb second-half free-kick and Peter Whittingham converted a penalty as Cardiff maintained their 28-year hoodoo over Neil Warnock's side.
Jamaica international Rodolph Austin fired home a 30-yard thunderbolt for Leeds with 13 minutes left, but Mackay's side held on to secure their third Championship win of the season.
Mackay said: "Half-time changed the game. Leeds came and worked very hard, were compact and disciplined.
"They negated space in the wide areas and did their homework by watching our game against Wolves.
"We spoke at half-time, upped the tempo and attacked them in different areas in the second half. We had 19 chances at goal and Paddy Kenny made three or four magnificent saves. On another day we could have scored four or five.
"After half-time we looked a different team. It's early days in the division, but I'm delighted with the win."
Leeds have not beaten Cardiff since a 1-0 win at Ninian Park back in February 1984 and have now failed to get the better of their Welsh rivals in 14 meetings.
Leeds boss Neil Warnock said: "I thought we deserved a point. But to lose Ross McCormack after three minutes was hard, he's our only Bellamy.
"Ross has twisted his ankle quite severely. I don't think there is any break, but we can't tell yet because of the swelling. I'd imagine he'll be out for a few weeks.
"It was a fantastic goal by Bellamy, but we were very disappointed with the free-kick that was given. Maynard is good at it. Michael Tonge pulled out of the tackle and he's gone down. The referee has given the free-kick. We should have had the wall better and were naive."