Hill’s swim was the highlight of the fourth night of competition in Dublin.
Shane Ryan came close to matching her achievement, narrowly missing the Olympic standard in the 100m freestyle.
Ryan, who is looking to make his third Games, lowered his own Irish Senior twice, first in the heats and then again in the semi-finals to 48.49 but needs 48.34 in the final on Sunday evening.
Galway backstroker John Shortt won the 200m backstroke in 1:58.38 but was shy of the Olympic time of 1:57.50 while Ellen Walshe, already Paris bound in the 200m individual medley, failed to make the time needed in the 100m butterfly.
Victoria Catterson edged out Grace Davison in the semi-finals of the 200m freestyle and will race again in the final on Sunday.
Nathan Wiffen was the fastest qualifier for Sunday’s 1500m freestyle final where he will attempt to join his brother Daniel in Paris.
Tom Fannon, Daniel Wiffen, Ellen Walshe, Mona McSharry and Hill are the Irish swimmers to have qualified for the Games to date.