The English boxer retained his International Boxing Federation and World Boxing Association world heavyweight titles with a devastating display of his punching power to finish Cameroon's France-based challenger at the Principality Stadium.
Takam became Joshua's 20th consecutive knockout victim in a fourth defence of his IBF belt and first of his WBA title, but the challenger stubbornly resisted the champion after being cut by the right eye in the fourth round.
"It was a good fight until the ref stopped it. I have the upmost respect for Takam," said Joshua, who injured his nose from a headbutt in the second round.
Takam was also given a count in the fourth round before being finished off by a barrage of unanswered punches which prompted the referee Phil Edwards to stop it.
Also Read
Takam complained it was a premature stoppage, which was jeered by Joshua's fans, and the challenger was given warm applause afterwards.
"I don't think they should have stopped it," said Takam.
Takam, 36, had only accepted his first world title shot at less than two weeks' notice and fought for most of the fight with a gruesome cut which obscured his vision.
For Takam, it was a fourth career defeat after a points loss to Parker last year and knockout loss to Russia's Alexander Povetkin in 2014.
Takam, who boxed for Cameroon at the 2004 Olympics before relocating to Paris a year later, was drafted in as a late replacement opponent at 12 days' notice after Bulgaria's Kubrat Pulev injured a shoulder.
Joshua landed a good left-right combination in the second round, but did not have as much success in the third.
In the fourth, Takam suffered a nasty cut by the right eye from a big right from Joshua which caused him problems instantly with his vision due to the blood.
When the fight continued, Takam was caught by a left that sent him spinning and was given a count as his glove was ruled to have touched down.
Takam had some of his best moments of the fight in the seventh round as he repeatedly caught Joshua.
Joshua tried to regain momentum in the eighth with two left hands that shook Takam, who was inspected by the ringside doctor at the start of the ninth round.
Takam was allowed to fight on but in the tenth he was shook by a right to the head and as Joshua unloaded more punches that landed flush, referee Phil Edwards stopped the fight.
Ireland's Katie Taylor won a world title in her seventh professional fight after unanimously out-pointing Anahi Sanchez for the vacant WBA lightweight belt by three scores of 99-90.
England's Kal Yafai also unanimously out-pointed Japan's Sho Ishida in a second defence of his WBA world super- flyweight title, winning by scores of 118-110, 116-112 and 116-112.
Disclaimer: No Business Standard Journalist was involved in creation of this content