On Tuesday, the decision-making body of the National People's Congress appointed his predecessor, Wang Yi, to take over the post.
Qin was last seen in public on June 25 in a meeting with counterparts from overseas. Officials at first said he was suffering from health problems before claiming that they had no other information to offer.
All mention of Qin has been scrubbed from the foreign ministry's website, and his profile page is blank.
Career diplomat known for close ties to Xi, hardcore stance
The 57-year-old former minister studied international politics at a university in Beijing and joined the Chinese Communist Party at the age of 20.
After graduating from university, Qin started his career as a diplomat at the Chinese Foreign Ministry, where he covered European matters and spent many years working at the British embassy.
Qin served a total of more than eight years as a foreign ministry spokesperson before he was promoted to vice foreign minister in 2018. He also served as the head of the protocol bureau.
He was appointed ambassador to the United States in 2021. The following year, he became foreign minister, replacing his predecessor – and now successor – Wang.
Qin was said to be one of President Xi Jinping's most trusted officials.
Korogi Ichiro, a professor at Kanda University of International Studies said Qin is believed to have been personally close to Xi when he was chief of the protocol bureau.
"Qin had a quick rise to the position of foreign minister, and his appointment over more experienced candidates may have caused some jealousy," Korogi said.
Qin had become known for aggressive foreign policy.
During talks with US Secretary of State Antony Blinken in Beijing in June, Qin directly told Blinken that the bilateral relationship was at its worst since the normalization of diplomatic relations.
China provides no details as rumors spread online
China has provided no details on the sudden personnel move.
Foreign Ministry Spokesperson Mao Ning said at a news conference on Wednesday that there was no information to provide regarding the matter, when she was asked about the reasons for Qin's replacement.
Korogi said authorities may have been investigating Qin after he was reported to have had a personal problem within the Chinese Foreign Ministry.
Rumors are spreading online, including a Taiwanese media report that Qin's relationship with a female newscaster at a Hong Kong TV station had come under scrutiny.
Korogi cited the possibility that a person close to Qin could be intentionally leaking information.
"I feel that there is someone who is actively disseminating information. There are many stories coming out that only people who are close to him could know," Korogi said.
Japan to continue to closely communicate with China
Japan's Chief Cabinet Secretary Matsuno Hirokazu has stressed that Japan will continue to closely communicate with China, and with Qin's successor Wang.
"It is important to build a constructive and stable Japan-China relationship through mutual efforts," Matsuno said at a daily news conference on Wednesday.
US says move will not derail relations with Beijing
US Secretary of State Antony Blinken said Qin's absence will not derail Washington's efforts to forge closer ties with Beijing.
"It is important for us to manage this relationship responsibly. That starts with diplomacy. That starts with engaging. And I will work with whoever the relevant Chinese counterpart is," Blinken said at a news conference during his visit to Tonga on Wednesday.
"I've also known Wang Yi for more than a decade. I've met with him repeatedly. I anticipate being able to work well with him as we have in the past," he added.
Analysis: Impact limited but long-term concerns remain
NHK World's Beijing correspondent Nakamura Genta said confusion and outrage are growing in China over how this move makes the country look on the world stage.
He cited a post on Chinese social media which questioned the meaning of Qin's departure after just under a year. Another poster responded that the scandal around the foreign minister was a "disgrace" for China's global image.
Qin was in the spotlight as recently as last month, Nakamura said, after he met with Blinken. He added that there was even talk of a future trip to Washington.
Nakamura said Qin's sudden fall from grace perhaps makes some Chinese people uneasy about how strong their leaders really are, and could certainly have a detrimental effect in some areas. But he said he believes its impact will be mostly limited.
Qin's replacement Wang has already attended a foreign ministers' meeting in Indonesia and met with senior American officials, Nakamura noted.
"Wang has a lot of experience with US diplomats, so we can assume he'll pick up the slack," he said.
But Nakamura said concerns remain that the move could affect the image of Xi's administration and have ripple effects, such as consequences for officials who vetted Qin's conduct prior to his appointment as foreign minister.
"Beijing is incredibly image-conscious, especially when it comes to accountability among top leadership," Nakamura said. "Whether the rumors about Qin are true – or not – this has been embarrassing."
He said the move "could impact the stability of Xi's administration, which of course, the US will be watching closely."