Born in a rural village in Guangdong Province, China, Hoo moved to Jamaica with her family in the late 1950s, developing a liking for Jamaican fruitcake during her residence there. She helped tend a grocery store in Jamaica, Welcome Supermarket, with her husband, Hoo Shue, despite never learning English; she instead communicated in Hakka, a Han-Chinese dialect.
Reported to be an excellent cook, Hoo would often cook roasted chicken, fried rice, and Chinese-Jamaican dishes, including yam and pork, for her family. She had two children with her husband; her daughter eventually gave birth to eight children.
In the 1970s, Hoo moved to Thornhill, Ontario, Canada, with her children, her husband having predeceased her by several years then. In 1994, she moved into a nursing home in Scarborough, Ontario, as one of its first residents.
She was described as "quiet and reserved, but smiled a lot". She was also said to have indulged herself with fried chicken and caramel popcorn, reportedly never having a poor appetite or losing any weight while at the nursing home.
Confined to a wheelchair in her last few years owing to a hip injury, Hoo was eventually bedridden in her last few years, a condition described by her family as a "far cry" from her earlier years, during which she was described as strong and independent.
Hoo's last appearance in the media before her death was on 13 December 2006, when she was congratulated in light of her claimed 111th birthday. She eventually died on 5 January 2011, at the alleged age of 115 years, 18 days; her claimed age, if correct, would have made her the oldest living person when she died. However, even if her claim was accurate, there is a possibility of her having been 114 at the time of her death, owing to the East Asian method of age counting where babies' ages are considered to start at 1 instead of 0. At the time of the death, the world's oldest sufficiently validated supercentenarian was recognised as Eunice Sanborn of Texas, USA (20 July 1896 – 31 January 2011). However, this rank then is now retroactively held by Maria Gomes Valentim of Brazil (9 July 1896 – 21 June 2011), whose age was validated four months after Hoo's death.