The undefeated puncher looked on his way to an routine win in the first round and had Whyte in trouble early on.
Whyte came back to rock Joshua for the first time in his career and raise some question marks about his chin and stamina.
Over the next few rounds, Joshua regained his rhythm, and eventually his momentum, to open up a lead through six rounds.
In the seventh, Joshua had Whyte hurt, and as the Olympic champion walked ‘The Villain’ down, unleashed an almighty shot towards the ropes.
There was no getting up from Whyte who was out of it as he lay prone on the canvas – leaving Joshua to add the British belt to his Commonwealth version.
In the co-feature at the O2 Arena, Chris Eubank Jr produced an impressive display to retire concrete-jawed Gary O’Sullivan before the eighth round.
Using his preferred piledriver uppercut and willing to trade at a moments notice with the Irishman, the Brighton man possibly booked himself a knockout night against Danny Jacobs in 2016.
Trading wildly at times, both men were going for the KO from the off, although it was the pre-fight favourite who came away with the win.
O’Sullivan’s corner made a wise decision to pull out their man at the end of the seventh as Eubank was certainly on his way to a wide points victory or maybe late stoppage.
Unknown quantity Ismael Barroso announced himself on the world stage by halting Kevin Mitchell in the fifth round.
Barroso rocked Mitchell in the very first round and had Mitchell scrambling for one big punch thereafter.
The win means Barroso moves on to fight WBA belt holder Anthony Crolla who witnessed the fight from a ringside seat.
Tony Bellew became the new European cruiserweight champion with a hard-fought points victory over tough Pole Mateusz Masternak.
The ‘Creed’ star had to overcome some eye damage to get the job done but moves ever closer to another world title shot with a 115-112 (twice) and 115-113 triumph.
Olympic gold medallist Luke Campbell suffered a shock first loss to Yvan Mendy when on the wrong end of a split decision. The 28 year-old lost unanimously by all accounts having been dropped and out-worked by Mendy, although the judges somehow came back with scores of 115-112 and 115-113 for the Frenchman, with one giving it to Campbell 115-113.
A rematch could follow as Campbell’s plans for a 2016 world title shot hit an unexpected snag.
Paulie Malignaggi recorded a decisive points victory over late substitute Antonio Moscatiello as the Italian-American picked up the EU welterweight title.
The veteran former two-weight world champion had too much class and experience for his compatriot and won a 120-109, 119-110 twice victory on the cards.
Dereck Chisora had no problems taking out also-ran Jakov Gospic to score a second knockout win in seven days in the third round.