Nigel Pearson's side overcame Sheffield Wednesday 2-1 at the King Power Stadium on Friday, meaning that if QPR lost at Bournemouth and Derby failed to defeat Middlesbrough then Leicester would be promoted to the top flight for the first time since 2004.
That was confirmed when QPR fell to a 2-1 defeat at Dean Court, while a solitary Nathaniel Chalobah goal was enough for Middlesbrough to beat Derby at the Riverside Stadium, meaning the champagne corks could be popped in Leicester.
Bournemouth moved ahead against QPR when Tommy Elphick headed home a routine corner on the stroke of half-time before Harry Redknapp - a former manager of Bournemouth - saw his side draw level almost immediately after the break through Armand Traore.
However, the hosts were in front again on the hour mark when Lewis Grabban reacted quickly to tap home Yann Kermorgant's initial saved effort and though Harry Arter was dismissed for a two-footed lunge on Junior Hoilett in the 68th minute, Bournemouth held on.
In the other decisive game at the top, Steve McClaren took his Derby side back to his old stomping ground of Middlesbrough, but it was to prove an unhappy return thanks to Chalobah's second-half winner.
Burnley remain second, 10 points clear of QPR, as Scott Arfield's 86th-minute leveller earned them a 1-1 draw at Watford, who had led through Troy Deeney's early opener.
And Reading retained their grasp on the final play-off position as Danny Williams' goal gave them a 1-0 triumph at lowly Charlton.
Fellow play-off hopefuls Wigan Athletic inflicted a fourth straight league defeat on Leeds United in the day's early game, as Martyn Waghorn celebrated his permanent move to the DW Stadium with the only goal of the contest.
There was good news for Leeds off the pitch, however, as Massimo Cellino successfully won his appeal against the Football League's decision to block his potential takeover and is now poised to assume control of the Yorkshire side.
In the play-off chasing pack, Brighton and Hove Albion could only manage a 0-0 draw at relegation-threatened Barnsley, who had Kelvin Etuhu sent off for two bookable offences late on, while Ipswich Town suffered a 2-0 defeat at Blackburn Rovers and Nottingham Forest were beaten 2-1 at home to Millwall.
Yeovil Town remain bottom of the league, but Gary Johnson's men defeated Blackpool 2-1 thanks to James Hayter's penalty and Tom Lawrence's strike.
The result leaves them three points away from safety, while Blackpool are just six points above the drop zone.
In other matches, Birmingham City alleviated their own relegation fears with a 3-1 triumph over Doncaster Rovers at the Keepmoat Stadium, with on-loan Manchester United striker Federico Macheda scoring twice against the team with whom he enjoyed a temporary spell earlier this season.
Bolton Wanderers triumphed 1-0 at Huddersfield Town with a 90th-minute winner from Joe Mason.
