Margaret McCarthy's  poetry has appeared in numerous literary magazines, journals and anthlogies. Selected publications include: The Pagan Muse:Poems of Ritual and Inspiration, Working Papers in Irish Studies, Gargoyle Magazine,  Shaking Like A Mountain: On line Literature about Contemporary Music, Poetry New Zealand, California State Poetry Society Quarterly, Caprice, Matrix, The Poet, Xanadu, Poets and Peace International, O!!ZONE, Voices International, Encore, Visions of the Enchanted Spirit, Nit & Wit Literary Magazine and The New Earth Review.  McCarthy has also reviewed for Groundswell Magazine, New Directions for Women and The Chiron Review.

McCarthy's stage plays use  the heightened language of her poetry as their basis.  The Sacrificial King: A Play for John Lennon  was given a New York City showcase production by The World 3 Theatre Company.  Prior to that, it was given staged readings at The English Speaking Union in New York City and at Duke University, N.C.  Its 2009 production at John Hancock Theatre, Boston, as part of The Boston Globe sponsored Massachusetts High School Drama Guild (MHSD) Festival took festival awards.

Her stageplay, Deirdre Retrograde is based on her own cycle of poems about the heroine of Irish myth. It resulted from McCarthy’s ongoing involvement with the literature of Celtic myth, which has been a continual source of inspiration for her creative work. The play was read at La Mama Theatre, NYC, as part of its Experiments Reading Series.

She is a member of The Dramatists Guild, PEN America and The International Women’s Writing Guild.

McCarthy has read her poetry at a variety of venues in the New York area, including WNYC FM's "Poetry in the Morning". She has been a guest at The Virginia Center for the Creative Arts, The Ragdale Foundation and The Hambidge Center, all of which have awarded her writing fellowships.