He then lectured at Rice University, and returned to Johns Hopkins University with the rank of associate professor at the young age of 25. In 1928 he was promoted to Professor and became only the fourth head of the Department of Mathematics (after J.J. Sylvester, Simon Newcomb and Frank Morley). After his retirement in 1949, he worked at the Instituto Tecnológico de Aeronáutica near São Paulo, Brazil, but returned to Baltimore in 1959. He continued working as a consultant for the Marine Engineering Laboratory; his last publication appeared in 1972.
^Lewis, D. W. (2003). "'To the Glory of God, Honour of Ireland and Fame of America': A Biographical Sketch of Francis D. Murnaghan". Mathematical Proceedings of the Royal Irish Academy. 103A (1): 101–112. doi:10.3318/PRIA.2003.103.1.101. JSTOR20459847.