Chris Hackett's clinical first-half strike secured three precious points as the resurgent Lions clinched their third successive win.
Caretaker boss Willie Donachie's case to be handed the managerial role on a permanent basis was further strengthened as his men made it four games unbeaten since he took temporary charge.
Admittedly The Lions' goal led a charmed life at times against the battling Cherries who were keen to impress their new manager Kevin Bond in his first game at the helm.
But the luck that at times seems to have been in such short supply at The Den, was there aplenty as Bournemouth hit the woodwork and squandered a hatful of chances in the second-half.
By that stage The Lions had already edged ahead in first-half stoppage time when Hackett picked up the ball just inside his own half and tore into the heart of the visiting defence before slipping a ball through to Danny Haynes. Although the latter's shot was blocked, the ball fell to Hackett who kept his cool and calmly despatched a shot into the bottom corner from 18 yards.
Millwall's first-half advantage was no more than the home team deserved, having recovered from a nervy start to settle into their stride and create some decent chances.
Samy Mawene's drive was well held by Gareth Stewart, Hackett drove over before Poul Hubertz lashed an angled drive wide before Danny Senda's deep corner was headed behind for a corner.
But the game turned in 60 seconds before the break when Warren Cummings' fierce was pushed onto the foot of the post by Pidgeley before the ball was scrambled clear, and a minute later Hackett had put The Lions ahead.
Millwall could have doubled their tally shortly after the re-start when Haynes met Alan Dunne's pinpoint free-kick, but the young loan striker glanced his header a yard wide.
Dunne then saw his 58th-minute effort float just past the post, but then the pendulum swung Bournemouth's way and the visitors produced a sustained period of pressure.
Darren Anderton was denied by Lenny Pidgeley's 64th-minute tip-over and then James Hayter placed a header inches over with Pidgeley stranded.
Neil Young hooked an effort wide and it then took a superlative full-length save by Pidgeley to tip Steven Foley's 84th-minute piledriver round for a corner.
But The Lions regrouped for one last time and withstood a final surge of pressure from the visitors to hold on for victory.

Millwall: Pidgeley, Senda (Phillips, 67mins), Craig, Elliott, Ross, Shaw, Dunne, Mawene, Hubertz (Zebroski, 83mins), Haynes, Hackett (McInnes, 90mins). Subs not: Day, Trotter.
Booking: Dunne (53mins)
Scorer: Hackett (45mins)

AFC Bournemouth: Stewart, Young, Purches, Maher, Best, Fletcher (Pitman, 86mins), Hollands (Foley, 78mins), Anderton, Cummings, Gowling, Hayter. Subs not used: Moss, Hart, Cook.

Ref: Steve Tanner
Att: 9,838 (Away 702)