Two goals just before half-time helped move Leeds to third in the table, inflicting a first away defeat of the season on Brighton in the process.
Luciano Becchio got the first, firing home from eight yards at the second attempt, before Jermaine Beckford headed in Fabian Delph's cross.
Beckford added a third in injury time, calmly finishing with Delph again providing the assist.
Glenn Murray got a late consolation from 12 yards for Brighton.
Leeds: Lucas, Richardson, Michalik, Marques, White, Hughes, Delph, Kilkenny, Douglas, Beckford, Becchio.
Subs Not Used: Ankergren, Prutton, Howson, Robinson, Snodgrass.
Booked: Kilkenny, Michalik, Beckford.
Goals: Becchio 44, Beckford 45, 90.
Brighton: Kuipers, Whing, Elphick, Hawkins (Cox 46), Richards, Anyinsah, Thomson, Savage, Livermore (Thornton 47), Murray, Virgo.
Subs Not Used: El-Abd, Robinson, Fraser.
Booked: Livermore, Hawkins, Elphick, Virgo, Thomson.
Goals: Murray 90.
Att: 22,726
Ref: Carl Boyeson (E Yorkshire).
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