[2] After his brother's death, Tom Pendergast served in the city council until he stepped down in 1916 to focus on consolidating the factions of the Jackson County Democratic Party.

[2] Pendergast married Caroline Snyder in February 1911 and raised three children (two girls and a boy) at their home on 5650 Ward Parkway.

Pendergast tried to portray a "common touch" and made attention-grabbing displays of helping pay medical bills, providing "jobs", and hosting famous Thanksgiving and Christmas dinners for the poor.

Among the projects were the Jackson County Courthouse, in Downtown Kansas City, and the concrete "paving" of Brush Creek, near the Country Club Plaza.

Pendergast placed many of his associates in positions of authority throughout Jackson County and exercised strong influence in determining the Democratic candidates for statewide office.

Pendergast also extended his rule into neighboring cities such as Omaha, Nebraska, and Wichita, Kansas, where members of his family had set up branches of the Ready-Mixed Concrete company.

The Pendergast stamp was to be found in the packing plant industries, local politics, bogus construction contracts, and the jazz scene in those cities as well.

Pendergast had endorsed Stark, the heir to an agricultural fortune and known for promoting the Golden Delicious variety of apples, for governor in 1936.

Shortly after attending the Democratic National Convention in Philadelphia in 1936, he was taken ill and later diagnosed with colon cancer and was in poor health for the remainder of his life.

After serving 15 months in prison at the nearby United States Penitentiary, Leavenworth, he lived quietly at his home, 5650 Ward Parkway, in his later years.

When Truman's attempt at a clothing business failed in 1922, Jim Pendergast suggested that he run for a "judgeship" in eastern Jackson County (actually an administrative, rather than a judicial position).

[7] After Pendergast was convicted of income tax evasion, Missouri Governor Lloyd C. Stark sought to unseat Truman in the 1940 US Senate election.

Two of his biographers have summed up Pendergast's uniqueness as a political boss:[14] Pendergast may bear comparison to various big-city bosses, but his open alliance with hardened criminals, his cynical subversion of the democratic process, his monarchistic style of living, his increasingly insatiable gambling habit, his grasping for a business empire, and his promotion of Kansas City as a wide-open town with every kind of vice imaginable, combined with his professed compassion for the poor and very real role as city builder, made him bigger than life, difficult to characterize.