The jury’s verdict was unanimous.
The 33-year-old father-of-five stabbed Ms Murphy to death as she walked along the Grand Canal in Co. Offaly on 12th January 2022 in a random attack.
Puska, originally from Slovakia, will be sentenced to the mandatory term of life in prison.
Judge presiding over the trial, Mr Justice Tony Hunt, praised the jury for not spending much time on what he called Puska's "nonsense," "because that is what it was."
He added: "Quite literally you made sure that nobody got away with murder."
Ms Murphy’s parents Ray and Kathleen, brother Cathal, sister Amy, and her boyfriend Ryan Casey were in the packed courtroom as the verdict was read.
The family applauded and held up a photo of Ashling as the jury left the courtroom at the Central Criminal Court.
Family members of Mr Puska were also present in court.
Victim impact evidence will be heard at a later date.
Puska will be sentenced on 17th November.
