At lunch on day one, the home side were 71 for two after winning the toss, with Warner on 42 and skipper Michael Clarke yet to score on a sunny day at Brisbane's Gabba ground.
Australia are bidding to avoid losing four successive Ashes series for the first time since 1890, but it was a good start for Broad, vilified for not walking during the teams' recent Tests.
Broad claimed the early wicket of Chris Rogers, and just before lunch, he added Shane Watson for 22 to go into the interval with figures of two wickets for 30 off eight overs.
Uninhibited opener Warner earned a bad boy reputation after he punched England batsman Joe Root in a bar before the last Ashes series, and earlier engaged in a Twitter war with journalists.
Warner took six runs off Broad's opening over and he unfurled a beautiful cover drive for four off James Anderson to race into double-figures.