The jury of six men and six women at Manchester Crown Court unanimously found Roughley, of Heaton Norris, guilty of unlawful act manslaughter.
Mrs Justice Ellenbogan adjourned sentencing until Wednesday and remanded Roughley.
During the trial the jury heard from prosecutors how Genevieve’s death was brought on by a ‘very unsafe sleeping environment’, created by Roughley.
The court was told Roughley had swaddled the child in a blanket and strapped her onto a bean bag, face down, to sleep.
On the day of the tragedy, Roughley was acting as baby room leader where she was one of only two staff looking after 11 children.
Jurors heard how Genevieve suffered fatal asphyxia and pathophysiological stress caused by the 'unsafe sleep environment' at Tiny Toes nursery in Cheadle Hulme, Stockport, on May 9, 2022.
The prosecution said the deputy manager had ‘showed hostility’ towards Genevieve Meehan in the days leading up to her death.
Defending Roughley, Sarah Elliott KC, said she looked after children in a ‘practical, responsible, no-nonsense but caring way'.
She said Roughley denied failing to make safe-sleep arrangements and had ‘kept an appropriate eye' on Genevieve.
