Cummins, who had been vice captain, replaces Tim Paine, who resigned last week over a sex-texting scandal.
After a week of speculation, Cricket Australia has confirmed Pat Cummins as the first fast bowler to captain Australia's test cricket team on a fulltime basis.
And former captain Steve Smith returns from leadership wilderness to become the team's vice captain.
Cricket Australia made both announcements on Friday. Cummins, who had been vice captain, replaces Tim Paine, who resigned last week over a sex-texting scandal four years ago.
The last fast bowler to lead Australia at test level was Ray Lindwall for a single match in 1956, and only as a stand-in. Cummins is Australia's 47th test captain.
Smith was fired from the captaincy after the ball-tampering scandal in South Africa in 2018. As well as losing the captaincy, he was banned from any leadership roles for two years.
“I am honored to accept this role ahead of what will be a massive Ashes summer,” Cummins said in a statement.
“I hope I can provide the same leadership Tim (Paine) has given the group in the past few years."
The first of five Ashes tests against England begins on December 8 in Brisbane.
“Pat is an outstanding player and leader," Cricket Australia chief executive Nick Hockley said. “He has earned enormous respect from his teammates and from all corners of the game for his attitude and achievements, both on and off the field."
Due to a variety of injuries, Cummins went more than five years between playing in his first and second tests. But he has not missed a test match for Australia since October 2018.
“With Steve and I as captains, a number of very senior players in this squad and some great young talent coming through, we are a strong and tightly knit group,” Cummins said. “This is an unexpected privilege which I am very grateful for and am very much looking forward to.”
Smith has played on teams with Cummins for more than a decade.
“I am pleased to return to the leadership of the team and look forward to helping and assisting Pat in any way I can,” Smith said. ”Pat and I have played together for a long time, so we know our respective styles well. We are also great friends.”
Cummins said he'll rely on Smith to take charge at various times during a match.