In a contest hugely dominated by the Magpies, who boasted 78% possession and 23 shots on goal, Leicester almost snatched all three points with their first shot on goal in the 93rd minute, only for Nick Pope to keep out a first-time volley from Timothy Castagne.
Nevertheless, a point keeps Eddie Howe's side third in the Premier League table and they cannot be caught by fifth-placed Liverpool, who sit four points further back with just one game remaining; Newcastle can now look forward to returning to the Champions League next season for the first time since 2003.
Meanwhile, Leicester - who themselves were competing in the Champions League six seasons ago - have climbed above Leeds United into 18th place but remain in danger of relegation as they sit two points adrift of 17th-placed Everton heading into the final weekend of the season.
The notable team news prior to kickoff was that James Maddison and Harvey Barnes were both named on the substitutes' bench for Leicester, with Dean Smith opting to select a five-man defence, while Joelinton was forced to pull out of Newcastle's first XI after sustaining an injury in the warm-up, with Elliot Anderson taking his place in midfield.
It was all one-way traffic in Newcastle's favour and the hosts made a lively start, with Alexander Isak and Miguel Almiron the two attackers in particular who looked the most likely to create an opening for the hosts.
Leicester looked fairly sturdy at the back, though, with centre-back trio Harry Souttar, Jonny Evans, Wout Faes preventing the Magpies from creating any real clear-cut opportunities, but the Foxes had virtually no threat going forward and struggled to break out of their own half.
The first half-decent chance fell to Newcastle's Anderson on the 22-minute mark, with the 20-year-old curling a long-range effort towards the far post that was comfortably collected by Daniel Iversen.
It was backs against the wall for Leicester towards end of the first half and Newcastle came close to breaking the deadlock in the 41st minute courtesy of some questionable goalkeeping from Iversen.
Following a Magpies corner, the Foxes shot-stopper failed to collect the ball when challenging 6ft 7in defender Dan Burn in the air, before Callum Wilson fired a strike from a tight angle against the near post before the follow-up was headed off the line by Wilfred Ndidi.
Almiron then smacked a left-footed effort against the other post just a minute later, before Wilson headed an in-swinging Kieran Trippier corner narrowly over the crossbar.
In desperate need of a creative spark, Leicester boss Smith decided to swap Kelechi Iheanacho for Maddison at half time, but that substitution failed to change the course of the contest as Newcastle continued to dominate proceedings.
The Magpies had to wait until the 58th minute to test Iversen between the Leicester posts, with Almiron weaving his way in front the right and picking out Isak in a central area before the Sweden international saw a powerful strike tipped over the crossbar by a strong right hand of the Foxes goalie.
Evans was struggling with an apparent tight hamstring and was taken off just after the hour mark along with Jamie Vardy, with a change of formation applied as Barnes and Patson Daka came on in attack.
For the third time in the match, Newcastle hit the woodwork in the 70th minute when a corner was flicked on by Faes, and Bruno Guimaraes somehow nodded the ball onto the back post from just a yard out, before Iversen kept out a low-driven shot from Sean Longstaff.
Leicester eventually experienced a decent spell of possession in the final five minutes of the match, and fired their first shot on target in the 93rd minute, with Pope called into action to make a massive save and keep out Castagne from around 12 yards out to ensure the Magpies secured the point required to qualify for the Champions League.
Newcastle travel to mid-table Chelsea on the final day of the season next Sunday, while Leicester will look to avoid relegation when they play host to West Ham United at the King Power Stadium.