He was special counsel for Allegheny County Emergency Relief in 1935.

He was special deputy attorney general of the Commonwealth of Pennsylvania from 1936 to 1939.

[1] Rosenberg received a recess appointment from President John F. Kennedy on November 20, 1961, to the United States District Court for the Western District of Pennsylvania, to a new seat created by 75 Stat.

He was nominated to the same seat by President Kennedy on January 15, 1962.

His service was terminated on July 2, 1999, due to his death in Highland Park, Pennsylvania, three days before his 101st birthday.