Dinniman Taught at Prince George Community College and West Chester University.[2]
Early political career
Dinniman's first elected position was as a member of Downingtown school district's board of school directors. He was first elected to this position in 1975, and held the post until 1979. In 1979, Dinniman was elected chairman of the Chester County Democratic Committee, a position he held until 1985.[1]
County Commissioner
Dinniman later served as Chester County commissioner for three terms, beginning in 1991. During his three terms as commissioner, Dinniman was the body's only Democrat.
Pennsylvania State Senate
2006 special election
After the death of Republican Senator Robert "Bob" Thompson in 2006, Dinniman sought and attained his party's nomination to run in the ensuing special election. The special election pit Dinniman against his fellow county commissioner, Republican Carol Aichele. In what was considered a political surprise, Dinniman won with 56% of the vote, becoming the first Democrat elected to represent Chester County in the state Senate since the 1920s.[3]
At the time of his retirement, Dinniman sat on five committees: Education; Communications and Technology; Agriculture and Rural Affairs; Environmental Resources and Energy; and State Government. He was the ranking Democrat on the Senate's education committee.[1]
Retirement
After initially preparing for a re-election campaign, Dinniman announced he would not seek another term and retire at the end of 2020.[9] He was succeeded by Carolyn Comitta.
Potential congressional candidacy
In 2009, the non-partisan political newspaper The Hill reported that Dinniman was "reportedly eyeing a run" for the Democratic nomination in the congressional seat being vacated by Republican Jim Gerlach, who was, at the time, running for governor.[10] Dinniman, however, ultimately did not enter the race.[11] He endorsed Manan Trivedi, a doctor from Reading, who went on to win the Democratic primary, but lost the fall general election to Gerlach.[12]
^"2008 General Election". Commonwealth of PA - Elections Information. Pennsylvania Department of State. 2008. Archived from the original on 2012-02-06.
^"2012 General Election". Commonwealth of PA - Elections Information. Pennsylvania Department of State. 2008.
^"2016 General Election". Commonwealth of PA - Elections Information. Pennsylvania Department of State. 2016.