An attorney by training, Peter left a lucrative private law practice in Chicago in 2004 to enter full-time public service. One year later, Peter founded a local not-for-profit, mobilizing hundreds of volunteers who have since served thousands of pregnant women in need and their children in DuPage and Will counties. He spearheaded the Chicagoland Project Gabriel campaign, which distributed tens of thousands of “Pregnant? Need Help?” bumper stickers throughout local churches to reach out to women in difficult and untimely pregnancies. In 2008, Peter joined the Thomas More Society*, a national not-for-profit law firm that focuses on the defense of First Amendment rights. During his first five years with the Society, Peter served as Executive Director & Legal Counsel, directing the Society's day-to-day operations. As Executive Director, he grew the Society substantially, setting fundraising records, retiring all of its long-term debt, and helping it to take on numerous lawsuits of national importance.

Peter has served as an elected Trustee on the Lombard Village Board since 2011, stepping in as Lombard's Acting Village President. He works full time as the Vice President and Senior Counsel of the Thomas More Society*. In that role, Peter represents churches, organizations, and individuals in state and federal courts across the country, and he regularly advises state and federal elected officials on the effects of proposed legislation. Peter is sought out by local and national television, radio, and print media as an expert legal analyst.

One of his first initiatives as a trustee was authoring and securing passage of the strongest municipal transparency policy in the state of Illinois, earning Lombard a rare 100% transparency rating from the Illinois Policy Institute. When he took over as Acting Village President, Peter initiated a line-by-line review of the Village's proposed 2013 annual budget, identifying and cutting over half a million dollars in spending without the loss of Village services. He then ensured that those savings were returned to Lombard taxpayers by permanently eliminating the Village's annual vehicle sticker and fee.

During his first two years as Trustee, Peter served as Chairperson of the Lombard Economic & Community Development Committee. Under Peter's leadership, the Committee took on numerous initiatives to help downtown Lombard and to improve the business climate generally in the village. He sponsored and worked to pass the Lombard "outdoor dining" program, rolling back unnecessary regulations to allow new outdoor dining options in the downtown area. He also started downtown Lombard’s “Outdoor Game Watches,” bringing in hundreds of new patrons to shop at local businesses. In order to encourage lower prices for taxi service and to allow Lombard-based livery businesses to grow, Peter rewrote the Lombard Taxi Ordinance to wipe away outdated regulations and to allow a wider variety of vehicles to residents' transport needs.

In 2009, Peter founded BanRedCams, a grassroots initiative that sought to ban unfair and punitive red light cameras in Lombard and surrounding communities. Lombard removed its cameras shortly thereafter. As a Village Trustee, Peter successfully worked to prevent garnishment of residents' state tax refunds to pay red light camera ticket fees.

Peter was elected to serve as State Representative of the 48th District on November 4, 2014. In 2017 he was elevated to the position of House Republican Floor Leader.

Peter earned his Bachelor of Engineering in Electrical Engineering from Vanderbilt University, completing the program in just 3 years. Peter earned his Juris Doctor from the University of Notre Dame, which he attended on scholarship. He is a member of Lombard's Father Boecker Council of the Knights of Columbus and is an Eagle Scout. Peter and his wife Margie attend Sacred Heart Catholic Church, where they have been parishioners for many years. They have one son, Matthew.