In traveling to Switzerland, he said he hoped his example would lead to debate and give more people the option of physician-assisted suicide.
"During the paperwork, he said 'what are we waiting for?'"
But in his final minutes, he listened to Beethoven's Ninth Symphony, best known for its last movement Ode to Joy, reportedly passing away shortly after the piece of music finished.
"I would have preferred to have (ended) it in Australia, and I greatly regret that Australia is behind Switzerland" when it comes to right-to-die laws, he said.
His last words before losing consciousness were: 'This is taking an awfully long time.' He died at 12.30pm in Liestal where he took advantage of Swiss assisted-suicide laws.
David Goodall told dozens of journalists who had gathered together into a small room at a hotel in the northern Swiss city of Basel on Wednesday, that he did not want to live anymore.
I am happy to have the chance tomorrow to end it.
He cited a lack of mobility but he was not ill.
Sky's Michelle Clifford said police and coroner officials would now need to visit the clinic to make sure the assisted suicide was carried out properly.
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Prof Goodall sang a few bars of the famous piece at his last press conference on Wednesday.
He did not a funeral, remembrance service or ceremony to take place as he had "no belief in the afterlife", Exit International said.
"My abilities have been declining over the past year or two".
Goodall was born 4 April 1914 in London, and in 1948 moved to Australia.
He and his family are using his highly publicized cases to push assisted suicide worldiwde.
In 2016, aged 102, he won a battle to keep working on campus at Perth's Edith Cowan University, where he was an unpaid honorary research associate.
"I would like being able to walk in the bush again, also see what is about me", added the father of four, who during his long life had three sisters.
With his grandson Daniel and a longtime nurse, Carol O'Neil, at his side, the renowned botanist and ecologist from Perth, Australia, entered the Lifecircle assisted-suicide center in Switzerland and began the final stage of the process by receiving a fatal dose of barbiturates.
Once named Australia's oldest working scientist, Goodall wished for his body to be donated to medicine or, alternatively, that his ashes be sprinkled locally.