Butler, who has overcome an achilles concern, was the most prolific forward in the Saints' 14.7 (91) to 7.21 (63) victory at Traeger Park on Sunday.
Ross Lyon's men banked just their second win in eight weeks, snapping a three-match losing streak and matching Melbourne with a 5-7 record.
The Demons failed to put enough pressure on their opponents and kicked themselves out of the contest, scoring 1.12 to the Saints' 5.3 in the second half.
Butler nailed three first-half goals and St Kilda kicked six of the first seven to open up a 31-point lead before quarter-time, laying the groundwork for their victory.
Nasaiah Wanganeen-Milera (29 disposals), Jack Sinclair (25), Callum Wilkie (31) and captain Jack Steele (23) were all influential.
Marcus Windhager (28 touches) and Zak Jones (20) also got busy while keeping tabs on Demons stars Kysaiah Pickett (12) and Clayton Oliver (16) respectively.
Melbourne, who were always playing catch-up, were well-served by Christian Petracca (22 disposals) and Judd McVee (20), while Steven May (21) fought hard to repel the Saints' attacking raids.
Isaac Keeler (three goals) was dangerous with two early majors for the Saints but their hot 6.2 to 2.2 first quarter was tempered by the loss of Mattaes Phillipou to a calf injury.
The Saints were also without star playmaker Wanganeen-Milera for most of the second term after a high bump from Aidan Johnson.
Johnson, a mature-age draftee, has already been suspended this season and faces further scrutiny for his latest indiscretion.
He could have been facing a lengthy ban, but Wanganeen-Milera returned to the action after passing a concussion test.
Oliver and Jones niggled each other at stoppages, as did Pickett and Windhager, in a fiery first half.
Petracca stood up with two goals in the second term and the Demons cut the margin to 13 points, despite kicking a wasteful 4.7 to 3.2 for the quarter.
Again the Dees failed to get bang for buck in the third term, winning the territory battle but failing to make it count on the scoreboard.
Butler's fourth goal gave the Saints a 17-point buffer at the final change and it was enough to keep Melbourne at bay.
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