The 3ft bird, who was left desperately ill after eating sand that he thought was snow, was taken back to the Antarctic on a research ship.
He was released down a slide into the water two months after he was discovered disorientated more than 1,000 miles from home.
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More familiar environment: Happy Feet is released in Antarctica from his big blue crate was four people try and encourage him to go down a specially-made slide and into the water 
Back home: Happy Feet prepares to be sent back into the sea two months after he was discovered in New Zealand But although he has been released, the penguin has been fitted with a tracking device so web users can keep track of where he goes over the next few months.
Vet Lisa Argilla, who looked after Happy Feet at Wellington Zoo, said she was pleased that he had been released back into the Southern Ocean.
She said: 'He slid down his specially-designed penguin slide backwards, but once he hit the water he spared no time in diving off away from the boat and all those "aliens" who have been looking after him for so long.'
F-f-f-f-Freezing: Happy Feet, who was found on a beach, prepares to go back into the sea for the first time in two months 
In he goes: The three foot tall emperor penguin slowly moves towards the water in Antarctica 
Gone: Happy Feet disappears for good. Web users will be able to track his progress online as he has been fitted with a GPS tracker Happy Feet, named after the 2006 film, was taken to the zoo after becoming sick on sand. He had also begun eating sticks and stones.
When he was finally taken to the zoo it was found his stomach was filled with beach debris and he had to undergo several operations to clear his system. Then he was kept in a special ice-filled quarters to copy the environment emperor penguins live in.
Finally given a clean bill of health, he was placed in a specially-designed crate filled with ice and loaded onto the research vessel Tangaroa.
Almost a week after leaving New Zealand, vets on board the ship decided today they had taken Happy Feet far enough south for him to be able to make his way onwards to the Antarctic.
Sea conditions were too rough for Happy Feet to be released by hand, so he was placed on a tarpaulin slide running from the boat's ramp.
'He needed some gentle encouragement to leave his crate, but then the release went really well,' said Miss Argilla.
Where he was found: The washed up emperor penguin walks along Peka Peka Beach in New Zealand - 3,000 miles north of its home in Antarctica 
Where he should be: Emperor penguins walk over the ice in Antarctica 
Life-saving: A team of medics operate on the penguin - named Happy Feet - who ended up 3,000 miles away from home and became sick after eating sand it mistook for snow. He was found on June 20 A team from the National Institute of Water and Atmospheric Research and the boat crew were all on deck to wave him goodbye.
'It's an indescribable feeling to see a patient finally set free,' said Miss Argilla.
Voyage leader Richard O'Driscoll told Wellington's The Press newspaper that apart from giving the veterinary team a few nips at feeding time, the penguin had been a well-behaved passenger.
'It's been a pleasure to have Happy Feet on board,' he said. 'We're just happy to help him on his journey home.'
But just in case he gets lost again, the wayward penguin has been fitted with a tracking device, which will eventually drop off, so the team - and the public - can follow his progress back home.
