Ricardo Gardner's 37th-minute strike proved enough to lift Sam Allardyce's side out of the bottom three and leave an injury and suspension hit Hammers in 12th place, just six points clear of the drop zone.
"It's been a long time coming," said Bolton boss Sam Allardyce after seeing his side inflict yet more away day woe on West Ham. "That was a very important victory for us after getting in front and then weathering a second half storm. I'm sure all Bolton fans will be as relieved as me because it's taken far too long to secure a win."
Both sides had made wholesale changes following their smarting midweek FA Cup exits. Now without the suspended Tomas Repka, Hammers also saw Trevor Sinclair (flu) and Don Hutchison (groin) fail to recover from that last-gasp defeat against Chelsea while Nigel Winterburn and Paul Kitson were rested. That resulted in Scott Minto and Hayden Foxe coming into a new-look back three alongside Christian Dailly, while Richard Garcia was handed his first Premiership start in midfield alongside Vladimir Labant, and Frederic Kanoute made a welcome return up front.
Wanderers also made five changes as debutant Dane Stig Tofting, a midweek signing from SV Hamburg, Bruno N'gotty, Simon Charlton, Paul Warhurst and Fredi Bobic each returned to a side that had crumbled to an embarrassing 4-0 FA Cup defeat at Tottenham Hotspur.
Allardyce, however, had always maintained that Premiership survival was top of the list for his slumping side, who had not won a single league game at the Reebok Stadium since late August.
But as both teams struggled to adapt to a powerful, awkward crosswind, the Trotters' manager must have been fearing the worst when Joe Cole unselfishly squared to an unmarked Jermain Defoe after ten minutes, only for the young Hammers' striker to see his low 12-yarder brilliantly beaten away by Jussi Jaaskelainen.
It was not long before the windswept Wanderers were causing problems of their own, though, and on the quarter-hour mark, 15-goal Michael Ricketts bulldozed in from the left before steering his angled shot into the side-netting.
And seconds later, the striker being touted for an England call-up should have opened the scoring when Tofting - making an impressive debut - sent him racing behind the square Hammers' defence, but with just David James to beat, his finishing was far from international class as he sidefooted tamely at the relieved 'keeper from ten yards.
At the other end, Kanoute carved out an opening for himself before turning and drilling low into the side-netting, and there was more bad luck for the Frenchman shortly afterwards when he joined Foxe - who had earlier been booked for an aerial challenge on Bobic - for supposedly diving.
Eight minutes before the break, though, the deadlock was finally broken when Hammers failed to clear Tofting's long throw and Ricardo Gardner's low 18-yarder flew back through the pack, past the outstretched toe of Bobic and inside the diving James' left-hand post.
In first half injury time Labant's sizzling 25-yarder cleared the bar by a whisker and seconds after the interval, Kanoute cut back for the sliding Cole who just could not steer the ball home.
And with the busy Hammers making a positive and pressing start to a second half they were destined to dominate, Kanoute hooked just wide of the angle from the edge of the area before two well-flighted Labant corners saw Garcia power a header past Jaaskelainen's right-hand post and Christian Dailly nod over.
The telling absence of the suspended Paolo Di Canio and Sinclair was there for all to see as Hammers placed more and more creative expectancy on the industrious Cole which, quite frankly, was too much of a burden to shoulder on one man alone.
In a bid to up the stakes in the one-way traffic, Paul Kitson was introduced at the expense of Garcia for the final quarter-hour. And although the Hammers' striker's injury-time header forced Jaaskelainen into a flying save, West Ham's miserable afternoon had already been underlined up by the frustrated Steve Lomas' late booking for dumping substitute Nicky Southall into the boards.
Minute-by-minute:
1 - A clash of heads in an aerial challenge leaves Foxe and Bobic grounded, but the pair thankfully return to their feet after treatment.
4 - After Cole is fouled, Labant's driven free-kick is deflected into the six yard box but is collected by Jaaskelainen.
6 - With the blustery conditions playing havoc, Defoe's attempted chip to Cole carries out to Labant, whose low cross almost reaches Kanoute but is cleared.
9 - Foxe booked for foul on Bobic.
11 - Labant's inswinging corner is punched out from under his own crossbar for another corner by Jaaskelainen.
12 - A great chance for the Hammers as Cole's determination on the left pays off and he feeds Defoe, whose instinctive low left-foot shot from 12 yards out is superbly pushed away by Jaaskelainen.
17 - Ricketts skips down the left and, despite the whole of the ball appearing to cross the line, is waved on by the linesman and allowed to cut inside before firing a weak shot wide of the target.
22 - Bolton miss a glorious chance as Tofting's lofted pass releases Ricketts and the striker bears down on James, seeming certain to score. Amazingly, he drags a weak shot straight into the arms of the stunned keeper, who immediately sets the Hammers on the counter-attack with a clearance that finds Kanoute. The Frenchman cuts inside two players on the right before firing in a low shot that flies just inches wide of the near post.
26 - Kanoute booked for diving.
31 - Schemmel's excellent tackle wins possession on the right and the Frenchman fires in a dangerous low cross that is partially controlled by Kanoute but then cleared for a corner.
35 - Gardner's corner is met by Bergsson, who loses Foxe and plants a header that James holds well. The Hammers keeper then releases Cole, who tries to find Defoe, but the young striker is muscled off the ball by N'Gotty.
36 - Warhurst booked for foul on Garcia.
37 - GOAL. Yet another blow just before half-time for the Hammers as Tofting's long throw isn't dealt with and the ball is touched back by Bobic to Gardner, whose stinging left-foot shot travels through the crowd and past the despairing dive of James. Bolton Wanderers 1 West Ham United 0.
Added time: 3 minutes.
45 - Substitution for Bolton, Southall replaces Warhurst.
45 - Labant's blistering left-foot shot from 30 yards out sails just over the bar.
Half-time: Bolton Wanderers 1 West Ham United 0.
Second half:
47 - Almost a great start for the Hammers as pressure from Defoe forces Jaaskelainen into a weak clearance that Kanoute collects before sliding the ball across the box to the onrushing Cole, who connects slightly but can't do enough to divert the ball goalwards.
50 - Cole's clever play in the box confuses the Bolton defence and the ball runs free to Kanoute, who hits an early volley that spins just wide of the target.
61 - Kanoute controls Minto's long pass on his chest but then fires an erratic effort well wide of the target.
62 - After some neat build-up play, Garcia's low effort is deflected away for a corner. From Labant's resulting kick, the young Australian powers a header just wide of the far upright.
68 - Another dangerous Labant corner finds Dailly unmarked in the six-yard box, but the Scottish defender somehow directs his point-blank header over the bar.
77 - Substitution for West Ham, Kitson replaces Garcia.
80 - Lomas booked for foul on Southall.
82 - Kanoute combines well on the right with Kitson, who cuts the ball back for Cole to fire in a shot that is deflected over the bar for a corner.
83 - Substitution for Bolton, Holdsworth replaces Ricketts.
86 - Labant's deep cross finds it's way through to Schemmel, who fires in a snapshot volley that Jaaskelainen holds well.
86 - Substitution for Bolton, Hansen replaces Bobic.
Added time: 2 minutes.
90 - Defoe's hanging cross is flicked on by Kanoute to Kitson, whose diving header is plucked out of the air by Jaaskelainen.
Full-time: Bolton Wanderers 1 West Ham United 0.
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