Lavery's political career started in 2005 when he was elected as a Republican to two terms as mayor of Hackettstown serving until 2011. Additionally he worked on the Warren County Republican Committee and was a legislative aid to Leonard Lance He was appointed as the Commissioner for the Delaware River Joint Toll Bridge Commission on June 25, 2015, by governor Chris Christie. On June 26, 2017, he was elected to be the Chairman of the New Jersey Republican State Committee following his endorsement from gubernatorial candidate Kim Guadagno. As chairman he focused entirely on getting Guadagno elected governor and dispelling any criticisms towards her from other Republicans. When Guadagno lost the 2017 New Jersey gubernatorial election, Lavery resigned as chairman. He would be re-elected the chairman on December 15, 2020, following the resignation of his successor Doug Steinhardt after the 2020 election. During this second term he decried election integrity outlining a series of voting reforms he and the New Jersey Republican Committee would like to see implemented in the state. He would be replaced without opposition in 2021 by Bob Hugin, the Republican candidate for the 2018 United States Senate election in New Jersey, at the suggestion of the Republican candidate in the 2021 New Jersey gubernatorial election Jack Ciattarelli.
