Milner’s moment of glory arrived 14 minutes after he replaced the limping Harry Kewell.
Milner, who became the Premiership’s youngest ever scorer after leaving the bench at Sunderland on Boxing Day, proved it was no flash in the pan.
Leeds were already leading through Jonathan Woodgate’s 30th minute header - the central defenderÂ’s first goal for two years - when Milner struck just before the interval.
With his 17th birthday just a week away, Milner took a pass from Jason Wilcox, went past French World Cup defender Marcel Desailly as if he was not there and unleashed an unstoppable right-foot shot into the top corner of the net.
Milner was immediately besieged by his delighted team-mates who appreciated the goal's quality.
Although Woodgate’s header on the half-hour took a slight deflection off Chelsea defender William Gallas on its way into the net, the Leeds player was credited with the goal on his return to the side after injury.
Chelsea made seven changes to the side held to a goalless draw by Southampton on Boxing Day but they came up against a Leeds team with their confidence fully restored.
The Londoners deployed a double substitution at the start of the second half, Jimmy Floyd Hasselbaink and Enrique De Lucas replacing Albert Ferrer and Jesper Gronkjaer.
But De Lucas squandered their best chance, poking the ball inches wide after Woodgate had done just enough to put him off.