O'Brien was educated in
Dublin where she won prizes in the international competitions of London's
Royal Drawing Society. At 17 she spent a year in West Cornwall with
Stanhope Alexander Forbes and at 18 she took part in her first exhibition at the
Royal Hibernian Academy. It became difficult to study internationally with the outbreak of the
Second World War, and O'Brien took the opportunity to use her skills for the war effort and turned to mechanical drawing. However, it was as a botanical illustrator that she was best known. Her studio in
Limerick was always called
the piggery and was where she brought in the plants from her garden to arrange for her work. She continued to exhibit on a regular basis both with the RHA and private exhibitions around Ireland. On occasion she would use her art to raise funds for charities like Friends of St Luke's Hospital in Rathgar. ==Personal life==