Helen Moynihan was born in Marcus, Iowa in 1902. She was raised in Chicago, where she attended the Chicago Art Institute and Chicago Academy of Fine Arts. Moynihan worked as a commercial artist until she moved with her husband and children to Milwaukee in the thirties. There, she studied under Robert von Neumann, Charles Thwaites, Armin Hansen, and fellow female artist, Hulda Rotier Fischer.
Moynihan was most active during the forties and fifties. She is known for her portraiture and landscapes, completed through direct observation and photographs. The artist was also known to have worked with a variety of media including ink, conte, pastel, casein, oil, tempera, and drybrush.
Moynihan has exhibited both nationally and internationally including at the Art Institute of Chicago and the Milwaukee Art Institute.