She started as a full-time cinema musician, performing in a string quartet with Arthur Darley, George H. Brett and Joseph Schofield at the 1922 Irish Race Convention in Paris in works by Swan Hennessy and Henri Bast and also appeared in concerts at the Salle Gaveau.
After the launch of the Irish national broadcasting service, 2RN, in January 1926, O'Connor was recruited as violinist and leader to the station's emerging "orchestra" which developed out of Clery's Instrumental Trio.
On 26 November 1927, O'Connor led the orchestra at its first public symphony concert at the Metropolitan Hall, Lower Abbey Street, conducted by Vincent O'Brien.
{cn} She worked closely with Michael Bowles on a successful series of fortnightly public symphony concerts beginning in 1941, at first in the round room of the Mansion House, and from 1943 in the Capitol Theatre, Prince's Street, in which O'Connor regularly featured as soloist.
In 1938, she co-founded the Dublin String Orchestra, which she frequently conducted, and performed works by a wide range of contemporary composers including Brian Boydell, Arthur Duff, John Francis Larchet and Frederick May.