Sexton has started the last seven tests in the number 10 shirt as Ireland won the Six Nations with a grand slam and extended their record winning streak to 12 matches.
Sexton missed much of the early part of that run because he was touring with the British and Irish Lions and Schmidt may have considered the 32-year-old was deserving of a rest after a gruelling 12 months.
In the absence of regular skipper Rory Best, who will miss the series with a hamstring injury, Sexton was named as co-captain with Peter O'Mahony and so it will be the flanker who leads out the tourists at Lang Park.
Rob Herring will win his fourth cap after being named as the replacement for Best at hooker, where he will come up against the uncapped Brandon Paenga-Amosa, with the more experienced Sean Cronin backing him up from the bench.
Jack McGrath and John Ryan will complete a new-look front row but props Cian Healy and Tadhg Furlong, who boast 101 caps between them, were named among the replacements and will be looking to make an impact in the last half hour.
Another change from the side that beat England to seal the grand slam in March comes at outside centre where Robbie Henshaw returns in place of Garry Ringrose to partner Bundee Aki.
Jordi Murphy gets a runout at openside with Schmidt clearly hoping his mobility and high work rate will help nullify the twin threat of Wallabies flankers David Pocock and Michael Hooper.
Team: 15-Rob Kearney, 14-Keith Earls, 13-Robbie Henshaw, 12-Bundee Aki, 11-Jacob Stockdale, 10-Joey Carbery, 9-Conor Murray; 8-CJ Stander, 7-Jordi Murphy, 6-Peter O'Mahony (captain), 5-Iain Henderson, 4-James Ryan, 3-John Ryan, 2-Rob Herring, 1-Jack McGrath.
Replacements: 16-Sean Cronin, 17-Cian Healy, 18-Tadhg Furlong, 19-Quinn Roux, 20-Jack Conan, 21-Kieran Marmion, 22-Johnny Sexton, 23-Jordan Larmour.
(Reporting by Nick Mulvenney; Editing by Peter Rutherford)
