Her portrait Euphoria was favourite out of 85 works in the exhibition, presented as part of the festival last month.
Mundaring Bicentennial Scholarship Trust sponsor the annual $200 award for the art challenge, which is open to students aged 13 to 18.
The Year 11 student from Thornlie said she had been interested in art for as long as she could remember.
Her early interest was encouraged by her mother, who provided her with the tools to take the plunge.
She began taking the subject more seriously in Year 7, through the school�s visual arts program for gifted and talented students.
�The program gave me the resources to branch out and try a lot of different things,� Eleisha said.
�I�ve used different media, but at the moment I�m hooked on pastels.�
Preferring a naturalistic rather than abstract style, she based her award-winning artwork on the image of a young girl she found online.
She said she selected the picture because it projected the emotion she wanted to convey.
Her materials for the portrait features an ink underlay and pastels.
Eleisha would love to continue her interest in art and study interior architecture.