Danny McGuire produced a kicking masterclass on his final Leeds appearance to inspire the Rhinos to a record-extending eighth Super League title.
Castleford had won their previous eight meetings with their neighbours and eased to League Leaders' Shield success.
But the Tigers had no answer to Grand Final experts Leeds on their maiden Old Trafford appearance as they slumped to a 24-6 defeat.
Tom Briscoe gave Leeds an 11th-minute lead and they went into the break with a 7-0 advantage courtesy of McGuire's drop goal.
The Hull KR-bound half-back added a brace of tries and another one-pointer to cap a fine individual display either side of Briscoe's second try, although Leeds old boy Alex Foster had the last word.
TWEET OF THE MATCH
"Ruthless execution from @leedsrhinos - Confirms Brian McDermott as the best coach in the @SuperLeague era. Superb" former prop Jamie Peacock hailed his former club and coach.
McGuire. The veteran half-back helped launch Leeds' golden era with a title-clinching try against Bradford in 2004 and he was at his brilliant best as he became only the second Rhinos captain to lead the club to Grand Final glory. His kick laid on the opening try for Briscoe and that set the tone for a magical performance that also included a crucial try-saving tackle on Greg Eden at 6-0. Leeds will miss the local lad.
VALUE OF EXPERIENCE
Leeds had 12 players with Grand Final experience to Castleford's one and it showed as the Rhinos delivered a near-perfect Old Trafford performance in wet conditions. Classy Cas will come again but it will take them a while to get over a humbling experience.
SPOTLIGHT ON TECHNOLOGY
Who would be a video referee? Phil Bentham was in the box after James Child was given the whistle and he had a busy first half, ruling out tries for Kallum Watkins (knock-on), Jy Hitchcox and Briscoe (both obstruction). He twice overturned the on-field decision when there was an argument for allowing both if the incidents were viewed in full speed. While they were far from howlers and in the end did not affect the outcome, the Grand Final underlined the fallibility of review systems.