D. Donald Jamieson, 87, a Philadelphia lawyer who worked to reform the court system and rose to become president judge of the Court of Common Pleas, died Sunday, Dec. 15, of natural causes at his home in DeLand, Fla.

In addition to serving as a judge, Judge Jamieson also was an active civic leader who served as a board member for numerous charitable organizations, and was a mentor to politicians such as Gov. Ed Rendell and Sen. Arlen Specter.

A native of Philadelphia, Judge Jamieson grew up in the Frankford section, where he also met his wife, said his nephew, Lou Bond.

"His love for Philadelphia was unending," Bond said.

Judge Jamieson graduated from the Wharton School of the University of Pennsylvania in 1947 and completed a law degree at Penn three years later. During the Korean War he served as a captain in the Judge Advocate General's Corps, for which he received the Bronze Star.

He began his legal career as an assistant U.S. Attorney, then spent time in private practice until 1965, when he was appointed to the Court of Common Pleas. Five years later, he was unanimously elected president judge.

Judge Jamieson returned to private practice in 1977, when he became a named partner at the Mesirov Jaffe Cramer firm, which later became Schnader Harrison Segal & Lewis.

Municipal Court Judge Bradley K. Moss joined the same firm as a recent law-school graduate. He said he was struck by how accessible Judge Jamieson was, and willing to help up-and-coming lawyers such as himself.

"He was a very selfless person," Judge Moss said. "He was very interested in other people, and in all aspects of public service."

Except for his years as a member of the judiciary, Judge Jamieson was active in politics, and unsuccessfully ran for Congress in 1958. He later served as a mentor and political adviser for people such as Rendell, Specter, and Pennsylvania Chief Justice Ronald D. Castille.

Before retiring to Florida, Judge Jamieson also served on boards for organizations that included the Shriners Hospital for Children, the Citizens' Crime Commission, and the Philadelphia Council of the Boy Scouts of America.

In addition to his nephew, Judge Jamieson is survived by his wife, Nanette; a son, Douglas; a daughter, Hepburn; and a grandson.

A memorial service is being planned in Philadelphia for next year.