The hosts threatened to start Rivals Weekend with a big shock, Castleford edging the first half with greater defensive intensity and exciting attacking sets.
It was a thrilling opening 40 minutes, not deserving of a rare pointless half.
However, Leeds opened the scoring right after the break, Momirovski reacting instinctively to dot down after a mistake in the Tigers defence.
The second was more orthodox, with the centre finding space on the right wing to storm home to the right of the posts.
Castleford’s intensity dropped after that second score, their guile and determination running out as Miller latched onto another defensive mistake to add a third try.
Simm’s score briefly threatened a late comeback, but Miller capped off a fine individual display by scoring his second try, after Croft had broken the line in centre field.
The result takes Rhinos up to fifth, while Castleford remain second bottom, above London Broncos on points difference.
Castleford: Broadbent, Simm, Hodson, Wood, Senior, Richardson, Miller, Lawler, McShane, Watts, El-Zakhem, Mellor, Westerman
Interchanges: Horne, Hall, Vete, Johnson
Leeds: Miller, Roberts, Newman, Momirovski, Handley, Croft, Frawley, Oledzki, Ackers, Sangare, Bentley, Martin, Smith
Interchanges: Lisone, O’Connor, McDonnell, Goudemand
Referee: Aaron Moore