After graduating, Diehl moved to New York City and worked in advertising. He later worked in television production in Los Angeles, California. In 2001, he moved to his wife's hometown of
Whitman, Massachusetts, where he worked as a business development executive in the sign industry.
Massachusetts House of Representatives 2010 election Diehl began his campaign to represent the 7th Plymouth District on February 22, 2010. Diehl received support from previous representatives from the same district, including
Andrew Card,
Michael Sullivan, Ned Kirby, and
Ronald Whitney. Diehl also received the endorsement of U.S. senator
Scott Brown. On November 2, 2010, he upset incumbent
Allen McCarthy and was sworn in on January 5, 2011. He was a member of the Joint Committee on Ways & Means, Housing, Transportation, Global Warming and Climate Change, Personnel & Administration, and Rules.
2014 Tank the Gas Tax Movement Geoff Diehl was a lead supporter of the successful
ballot question campaign to repeal the Massachusetts gas tax indexing law in 2014.
2018 U.S. Senate election in
2022 Massachusetts gubernatorial election In April 2017, Diehl announced his intent to challenge
Elizabeth Warren for her
U.S. Senate seat. In the Republican
primary election held on September 4, 2018, Diehl finished first in a field of three candidates. The incumbent,
Elizabeth Warren, defeated Diehl by 24 percentage points.
2022 Gubernatorial campaign On July 4, 2021, Geoff Diehl announced he was running for
governor of Massachusetts. In October 2021, Donald Trump endorsed Geoff Diehl for governor. He was Massachusetts state co-chair of Trump's 2016 presidential campaign and a Trump delegate to the
2016 Republican National Convention. Diehl also supported
Jim Lyons, the chairman of the Massachusetts Republican Party, who in January 2021 was reelected to the party chairmanship after defeating a challenge from
Shawn Dooley. As a candidate, Diehl criticized federal and state mandates put in place during the
COVID-19 pandemic and continuously supported workers and first responders being fired for not taking the vaccine. He is a proponent of parents who want to decide for their children whether or not they would like a vaccine. At the state party convention on May 21, Diehl was officially endorsed by the Massachusetts Republican Party with 71% of the delegates' votes. He won the Republican nomination on September 6. On November 8,
Attorney General of Massachusetts and Democratic nominee
Maura Healey defeated Diehl in the general election. == Electoral history ==