In 1995, he joined the staff of the Hong Kong-based South China Morning Post. He was later promoted to the senior position of Beijing bureau chief, which meant he was in charge of all mainland content. In 2002, he lost his job, in an experience he writes about in a Washington Post column headlined "Why I Was Fired in Hong Kong."
Given his often critical views of China, his abrupt removal was considered by some to be a sign of deteriorating press freedoms in Hong Kong. Becker’s dismissal for "insubordination" was widely reported in the international media. He was fired after commenting that the paper was restricting his reporting and downplaying coverage on AIDS and labour disturbances on the Mainland. 
Becker's books include:
- The Lost Country: Mongolia Revealed (1991)
- Hungry Ghosts: Mao's Secret Famine (John Murray, 1996), about the Great Leap Forward Famine
- The Chinese (John Murray, 2000)
- Rogue Regime: Kim Jong Il and the Looming Threat of North Korea (Oxford University Press, 2005).
- Dragon Rising: An Inside Look at China Today (2007)
- Mongolia: Travels in the Untamed Land (2008)
- The City of Heavenly Tranquility: Beijing in the History of China (2008)
Becker has published both reportage and commentary for many news publications, including The New York Times, the International Herald Tribune, The Wall Street Journal, The Washington Post, The Globe and Mail in Canada, Business Week, the London Review of Books and the Times Literary Supplement.
He is considered an expert in Asian politics, and has appeared as a commentator on CNN and the BBC. American television networks often use him as a guest expert. He discussed the Tiananmen Square protests of 1989 with CBS's 60 Minutes and North Korea on ABC's Nightline with Ted Koppel, Primetime Live with Diane Sawyer, and ABC World News Tonight with Peter Jennings.
- Jasper Becker, "Why I Was Fired in Hong Kong," The Washington Post, 4 May 2002.
- Philip P. Pan, "Journalist is Fired after China Remarks," The Washington Post, 5 May 2002.