Olympic super-heavyweight champion Joshua is one of three British boxers afforded the honour in the new AIBA rankings, with fellow gold medallist Luke Campbell also rising to number one at bantamweight, and Welsh flyweight Andrew Selby retaining his place.
Speculation about Joshua's future followed the thrilling countback win over reigning champion Roberto Cammarelle at ExCeL which made him one of the most sought-after signings in the business.
But Joshua has steadfastly refused to commit himself, and now insists he will see out the remainder of his contract with the Great Britain amateur squad - due to run until March 2013 - before considering his options.
Joshua said: "I will still be boxing for Great Britain until my contract comes up for renewal, and I am delighted to do so as the number one in the world because it feels like the pieces of the puzzle are fitting together.
"I'm Olympic champion and world number one and I'm where I feel I ought to be. Being number one gives me a great feeling of fulfilment and proves that I'm no flash in the pan, that I belong there. To be ranked number one in any sport is one of the biggest things out there."
The 22-year-old Joshua has been determined not to let the fame he has experienced since clinching Great Britain's final gold of the Games affect him, insisting the biggest way his life has changed is being recognised at his local launderette.
"People are just happy because I'm a local boy from Finchley and people see me in the launderette or out running in the morning and they have an interest," added Joshua. "It's been easy in a sense. I just have to make sure I don't get lost in the hype.
"My feet are on the ground and I'm in a good position to be a voice for amateur boxing. I'm passionate about it and I can now make my voice heard to more people. But I am under no illusions that I still have work to do."