Behan grew up on Morehampton Road, Dublin, spending time in Glencree, County Wicklow.
She first attended NCAD as a day student, then moving to study in the evening while working as a temporary clerk.
When the couple were first married, she supplemented the family's income by working as a horticultural illustrator with The Irish Times.
Behan was tolerant of her husband's heavy drinking and behaviour, describing him as a "great, loveable genius."
After her husband's death she worked with Alan Simpson on the unfinished play Richard's cork leg.