The controversial Kyrgios has made the final four in three of his last four tournaments.
World number two Djokovic and his 2010 Davis Cup champions Serbia team had already booked their place in September's semi-final against nine-time winners France by beating Spain who were hamstrung by the absence of Rafael Nadal.
But firebrand Kyrgios needed to seal the deal for Australia on Sunday, securing the winning point in the first of the reverse singles to defeat 32-time champions United States.
That gave Australia a semi-final trip to Belgium who also had to wait until Sunday to wrap up a second last-four date in three years by seeing off Italy, the conquerors of defending champions Argentina in the first round.
Kyrgios's 7-6 (7/4), 6-3, 6-4 win over Sam Querrey gave the Australians an unassailable 3-1 in Brisbane.
The controversial 21-year-old Kyrgios revealed that Australian captain Lleyton Hewitt had asked him to be the team's leader and he had been happy to accept the challenge.
"I'm playing better, but I'm just in a happier place," said the world number 16.
Kyrgios pushed eventual champion Roger Federer to the brink in the semi-finals in Miami last week and has made the final four in three of his last four tournaments.
He said that during this run of good form he had always had one eye on the Davis Cup.
"I've been looking forward to this tie for a long time now," he said.
"I always had one eye on it. When I was in the States I always knew I had to come here and play two big matches."
Should Kyrgios and Djokovic make the final in September, the Australian will not be cowed by the challenge having seen off the world number two twice this year, in Acapulco and Indian Wells.
Belgium, the runners-up to Great Britain in the 2015 final, made sure of their semi-final place when national number one David Goffin eased past Italian veteran Paolo Lorenzi 6-3, 6-3, 6-2 in Charleroi for a 3-1 lead.
"There's a lot of time between now and September but Australia will be our focus," said Goffin who won both his singles at the weekend. "We are going to prepare well for it."
To nullify the big-serving Kyrgios, Belgium will opt for a claycourt surface if given the opportunity.
Djokovic reckons France, who made their fifth semi-final in eight years by beating Britain in Rouen, will also go for clay, either in Monte Carlo or even Roland Garros where he won his first French Open last year.
The 12-time major winner says all the pressure will be on France who lost the 2010 final to Serbia in Belgrade. France have lost three finals since their last title triumph in 2001.
"They have had so much success down the years," said Djokovic. "It's a very important tournament for them but they have come up short recently so they will be very hungry."
"They are likely to pick red clay. I am relishing the claycourt season as I felt I played really well throughout this Davis Cup week."