A rolling mill worker and union council member influential in the Amalgamated Association of Iron and Steel Workers,[1] he was elected to Pittsburgh City Council, serving four terms.

[2] He grew up in Muncie, Indiana and then moved to Pittsburgh, Pennsylvania in 1905 when he was elected as president of the Amalgamated Association of Iron and Steel Workers.

[3] McArdle's home in later life was on Bigham Street in the Mount Washington neighborhood of Pittsburgh.

[4] His son, Joseph A. McArdle, became a Pittsburgh city councilmember and United States Congressman.

[citation needed] A rolling mill worker and union council member who became influential in the Amalgamated Association of Iron and Steel Workers, Peter J. McArdle hosted the union's 1909 convention[1] and was also involved in the Steel strike of 1919.