The school's Coat of Arms is quite distinctive with a field of blue bearing a maroon saltier (a cross in the form of an X) signifying that the high school is under the jurisdiction of the Archdiocese of New York. Such a cross, called the Cross of Saint Patrick, is displayed on the coat of arms of the Archdiocese, where it represents the titular of the Cathedral.

The Lion rampant, the sole charge in white on a gold field, is from the coat of arms of the Farrell family of Ireland, and honors the late Msgr. Joseph A. Farrell whose name the school bears. The chief is charged with a chalice from the coat of arms of Saint Joseph's Seminary, Dunwoodie, Yonkers, New York, to represent the Diocesan priests who teach in the high school. This heraldic partition is also charged with a Celtic cross (emblazoned with a star), from the insignia of the Congregation of Christian Brothers, who also teach in the school.

The school's motto of Vir Fidelis - A Faithful Man, is derived from the Divine Office on the Feast of Saint Joseph where it is stated that "a faithful man shall be much praised, and he who is the guardian of his Lord shall be glorified". With this motto Monsignor Farrell High School heralds its ideal of Catholic manhood by attempting to present a program and lifestyle which, with God's help, will enable the students to cope with the challenge of living in the modern world.