[4] On April 18, 1867, Blankenburg married Lucretia Longshore (May 8, 1845 – March 29, 1937),[7] a Quaker suffragist, social activist, civic reformer, and writer.

He was then elected mayor of Philadelphia in 1911 on the Keystone-Democratic ticket; the coalition was organized to fight Republican corruption in the state and city.

He ended assessments by ward leaders of policemen, reorganized the civil service system to have it based on merit, gained passage by the legislature of a bill to enable the city to lease development of subway and transit lines, and worked for reform for 40 years as a political activist.

In 1921, the City of Philadelphia contracted with the John W. Sullivan Company of New York for the construction of a 129-foot, steam-powered, all-steel fireboat to be named the Rudolph Blankenburg.

[14] The boat was launched in Elizabeth, New Jersey on August 10 of that year, sponsored by Blankenburg's widow, Lucretia, who broke a bottle of champagne across its bow.

[16] That year, the Blankenburg and its running mate, the J. Hampton Moore (which was named after another mayor of Philadelphia), were replaced by a pair of diesel-powered fireboats, the Franklin and the Delaware.