Born and raised in Vancouver,^[4] Jang was the eldest of three siblings.^[5] His father, Leslie, was a Vancouver School Board (VSB) plumber for 20 years, and his mother, May, had an administrative career with the Provincial Court of British Columbia, taught Chinese cooking at the VSB's night school program, and sold cookware.^[4] Jang's paternal grandfather had three wives, of which Jang's paternal grandmother was third, and twenty-one children.^[5] Jang's grandfather made a fortune as a merchant after immigrating from China, but lost it all in the Great Depression.^[5] Jang's maternal grandfather was a pig farmer in China and became a tailor after immigrating to Canada.^[5]

He attended Renfrew Elementary School^[5] prior to Windermere Secondary School, where he was not a very good student.^[4] He worked on improving his academic record at Vancouver Community College and then transferred to Simon Fraser University to complete his Bachelor's and Master's degrees in Psychology.^[4]

He completed his education with a Ph.D. in Personality Psychology^[6] at the University of Western Ontario,^[4] where he initially studied under the highly controversial J. Philippe Rushton, known for work on race, intelligence and penis length.^[5] Jang has described the experience of witnessing Rushton's censure, and the impact it had on his understanding of politics:

"his theory was that Asians are the smartest people on earth. I didn’t believe it, because, mathematically, if you look at IQ scores there’s so much overlap, there’s no difference. He was wrong. He was censured by the university and I skeedaddled out of his lab within three months. What that taught me was the power of activism. People challenged him. They shut him down. I learned you can take on the big guy in a respectful way. It opened up a wide range of options."^[5]

In September 2006, Jang announced that he planned to seek the federal NDP nomination for the Vancouver Kingsway riding, after being called by Jack Layton, the leader of the NDP.^[7] The incumbent was David Emerson, who had crossed the aisle to the Conservative Party after the earlier election in 2006.^[7] Jang subsequently backed out of the race.^[8]

He was first elected councillor in the 2008 Vancouver municipal election under the Vision Vancouver banner,^[9] and re-elected in the 2011 and 2014 municipal elections.^[1] He was one of three elected city officials who served on Homeless Emergency Action Team,^[10] which conceived the controversial^[11][12][13] Homeless Emergency Action Team (HEAT) shelters.

In June 2014, Jang faced a court petition to remove him and fellow councillor Geoff Meggs from office for allegedly violating rules on conflict of interest in connection with the rezoning of a public housing project.^[14]

In October 2016, Jang came under fire from Chinese Canadians after participating in the raising of a People's Republic of China national flag on the grounds of the Vancouver City Hall, sporting a red scarf. The event, organized by the Canadian Alliance of Chinese Associations to mark China's National Day, is one of many flag ceremonies held at city hall. The Alliance of the Guard of Canadian Values, a group of mainland Chinese immigrants which has protested local celebrations of Communist leader Mao Zedong, started an online petition calling for Jang's resignation.^[15] "I was shocked," said Meena Wong, former mayoral candidate for COPE, "to have my city councillor in my city hall raising the flag wearing the symbol of loyalty to communism, I was dumbfounded." Jang tried to deflect criticism by suggesting that the Chinese Canadian protesters were "rooted in ignorance and racism. [...] To them it doesn't matter if it's a Communist government in China, they're just anti-Chinese."^[16]

Jang announced in January 2018 he would not run in the municipal election to be held in November that year.^[17]

Jang and his wife Vicki live in the Renfrew-Collingwood area of Vancouver.^[5] They have two children, Nicholyas and Rachelle.^[4]

• Kerry Jang at Vancouver City Council