Rockwell was ordained deacon in 1961 and priest in 1962. He began his priestly career at St. George's School, Middletown, Rhode Island (1961–69) and then moved to Rochester, New York where he served first as chaplain at the University of Rochester (1969–71) and then as dean at Bexley Hall Theological Seminary (1971–76). From there he moved to New York City in 1976 where he served for fifteen years as the fourteenth rector of St. James' Episcopal Church on the Upper East Side. Under his leadership St. James' initiated a ministry for the homeless and became one of the first churches to divest from investments in apartheid South Africa.[2]
In 1990 he was elected bishop coadjutor of the Diocese of Missouri, becoming bishop diocesan in June 1992. In November 2000, he announced his plan to retire in the summer of 2002.[4] He was succeeded by George Wayne Smith.
^Rice, Patricia (2000-11-19). "EPISCOPAL BISHOP SAYS HE PLANS TO RETIRE IN 2002: HE MAKES ANNOUNCEMENT NOW SO DIOCESE HAS TIME TO FIND REPLACEMENT". St. Louis Post-Dispatch.