He was a clerk for Judge Francis J. Catania of the Delaware County Court of Common Pleas from 1964 to 1972.
He was the chairman of the Delaware County Republican Executive Committee from 1972 to 1985.
He was a judge on the court of common pleas of the 32nd Judicial District of Pennsylvania from 1976 to 1987.
[2] In July 1982, Kelly presided over the rape-murder trial of Nick Yarris, resulting in the defendant's wrongful conviction and death sentence, which was not overturned until 2003.
Kelly was nominated by President Ronald Reagan on May 1, 1987, to a seat on the United States District Court for the Eastern District of Pennsylvania vacated by Judge Donald West VanArtsdalen.