Crowley struck 16 minutes from time when he jinked through several tackles to score his first Munster try, adding the extras to lead 17-12.
Jack Crowley’s first senior try for Munster proved decisive as Graham Rowntree’s side saw off a battling Cardiff in Saturday night’s BKT United Rugby Championship contest at Thomond Park.
Munster were forced into a late change as World Cup winner RG Snyman was unavailable due to illness. Tom Ahern took his place in the second row with Jack Daly coming on to the bench.
There was just one score in the opening half when Crowley broke the deadlock shortly before the interval with a penalty from 30 metres.
Earlier a try in the left corner from John Hodnett had been ruled out for a knock-on in the build-up.
Munster extended their lead eight minutes after the restart after a couple of penalties to the left corner, with skipper Tadhg Beirne squeezing over to score. Crowley converted to make it 10-0.
However, Cardiff hit back after 55 minutes when centre Ben Thomas intercepted inside his own 22 and raced to score under the posts. Tinus de Beer converted to cut the gap to 10-7.
Cardiff, who had not won in 10 previous visits to Thomond Park, edged in front going into the final quarter when hooker Liam Belcher scored after they went to the left corner with a penalty to lead 12-10.
Crowley struck 16 minutes from time when he jinked through several tackles to score his first Munster try, adding the extras to lead 17-12.
The out-half made the game safe with a penalty five minutes from time, although Cardiff got a late bonus point when replacement Jacob Beetham scored in the closing stages.