Needing to win by approximately 95 points at the start of the last match of the home-and-away season, the Saints did it easily at the finish, with the Bombers uncompetitive in a seven goal to nil final term that set up St Kilda's 21.21 (147) to 5.9 (38) victory.
St Kilda was on top all over the ground throughout the match, with consistent inaccuracy in front of goal the only danger to its top four ambitions.
Stephen Milne had a day out with seven goals, while Nick Riewoldt was a focal point all day, booting 4.5.
The Saints runners were all in top form with Brendon Goddard (30 possessions), Lenny Hayes (29), Jason Gram (27) and Nick Dal Santo (25) all making valuable contributions.
The Bombers managed the first goal of the match through Paddy Ryder, and looked to have a second on the board midway through the term before the umpires overturned their initial decision, judging that Saints defender Sam Fisher had touched his shot.
But it didn't take long for the Saints to take control. Hayes was everywhere, with his 12 first-quarter touches helping to drive his side to an early 20-point lead, a margin that would have been greater but for a few set shots that went astray.
Jason Johnson was set up by fellow retiree Adam Ramanauskas for the Dons' second, but that would be their last major for the half as St Kilda went about building on a 20-point quarter-time lead.
The Saints simply cut off the supply routes into the Essendon forward line for much of the second term, and on the nine occasions that the Bombers did find a way through, they were swiftly repelled.
The only concern for Saints coach Ross Lyon was the continued inaccuracy in front of goal, but St Kilda rolled on regardless. Riewoldt's third helping his side stretch its lead to 42 points at the main break.
Fourth spot looked there for the taking after the Saints bolted out of half-time with three goals inside four minutes, two of them by Milne.
Jobe Watson got one against the run of play as the Bombers managed to at least hold their ground with a nice snapped goal to Rhys Magin canceling out a fine long-range bomb on the run from Jason Gram.
Saints' fans had their hearts in their mouths as Riewoldt hobbled from the ground in pain, but he was soon back in action. Milne's third of the term blew the margin out to 68 points, but a late major to Essendon skipper Matthew Lloyd saw the lead cut to 61 points.
With the Bombers slowing to a standstill, St Kilda went about its task in methodical fashion in the last quarter with Milne's seventh the goal that put his side into fourth spot, with further goals to Adam Schneider and Riewoldt cause for celebration.
Essendon 2.3 2.6 5.8 5.9 (39)
GOALS
St Kilda: Milne 7, Riewoldt 4, Gram 3, Schneider 2, Eddy, Gardiner, Goddard, King, Montagna
Essendon: Johnson, Lloyd, Magin, Ryder, Watson
BEST
St Kilda: Milne, Gram, Riewoldt, Goddard, Koschitzke, Hayes, Fisher
Essendon: Ramanauskas, Peverill, Lonergan, Watson
INJURIES
St Kilda: Dempster (knee), Schneider (cork) but returned to field, Riewoldt (knee) but returned to field
Essendon: Lloyd (hamstring) but returned to field
Umpires: Nicholls, Head, Keating
The views in this story are those of the author and not necessarily those of the clubs or the AFL.