Axel Tuanzebe netted an extra-time winner in Guadalajara on Tuesday (Wednesday AEDT) to see them return to the finals after a 52-year wait.
The former England under-21 international bundled the ball over the line from a corner in the 100th minute, but had to wait for more than a minute while it was checked for a possible handball before being confirmed as a goal.
It was as much as the Congolese deserved, having dominated proceedings in a fast-flowing match without many clear-cut chances at Estadio Guadalajara, one of the three Mexican venues for the World Cup.
It is the second time DR Congo have qualified for the finals, more than half a century after their initial appearance in 1974, when the country was known as Zaire.
They are the 10th African country to have qualified, and at the World Cup they will compete in Group K against Colombia, Portugal and Uzbekistan.
Jamaica's veteran goalkeeper Andrew Blake made a sharp save to deny Cedric Bakambu at the start of the second half, before the Reggae Boyz enjoyed a dominant spell after being on the back foot for most of the first half.
During a 20-minute burst of dominance for Jamaica, Leon Bailey had their best opportunity in the 67th minute but put wide his diving header.
In the final 10 minutes, the Congolese wrestled back control, and after Theo Bongonda and Edo Kayembe had both gone close, they thought they had secured a dramatic late win when they had the ball in the back of the net in the 85th minute.
But Bongonda was marginally offside as he collected the ball before passing for Bakambu.
The pressure continued to extra time, but after some stout defending Jamaica will be disappointed with conceding from a corner as Tuanzebe netted his first international goal.