Hearn worked as house surgeon and house physician for the
Cork North Infirmary in Cork until 1922 when she was appointed to the Victoria Hospital Cork in 1922 as an honorary anaesthetist. The following year she joined the staff as assistant medical officer and then as the medical officer. Hearn was running a private gynaecological practice near
Shandon, Cork during this time as well as working with the Lapp's Charity, Cork. In 1922 Hearn got membership of the RCPI, and on 18 October 1924 became the first woman to become a fellow of the college. Hearn maintained her qualification through postgraduate courses held in London every year until 1968. An interesting side note about her is that her letter returning her fee for successfully sitting the membership examination for the RCPI was travelling through the GPO when it was damaged by the
Irish Civil War. It nevertheless was delivered to her, despite the damage, stamped with the note "Salved from GPO Dublin". Hearn gave dedicated service to the Victoria, serving on the board from 1938 and actively involved in the running of the hospital. Hearn showed great ability to attract donations to the hospital organising fund-raising events, both for the hospital and for her community. This made her famous among her colleagues. Her most popular annual fund-raiser was the tea and entertainment for outpatients at Christmas. She also held appointments as the medical officer to the Rochelle School, Cork, and
Midleton College, as well as that of honorary visiting physician to Lapps Charity in Cork. Outside of her medical career, Hearn was a keen hockey player and represented Ireland from 1908 to 1912. ==Family==