At the Abbey, she met and then married actor Ray McAnally in 1951, and they remained married until his death, although they resided in different homes; her husband with Irish actress Britta Smith.

McAnally and Masterson had four children; Conor, Aonghus, Máire and Niamh.

[1] They formed Old Quay Productions, which presented an assortment of plays such as Who's Afraid of Virginia Woolf?, The Odd Couple and many others.

She has appeared on many series broadcast on RTÉ, BBC and ITV and toured extensively in the United States in her own one woman shows.

In November 2005, she was in the United States again, this time to take the lead role in The Sea Captain, a short film directed by her son, veteran television producer Conor McAnally.