Mahern was born on September 11, 1963 in Indianapolis, Indiana, United States and grew up in the American Midwest. As a teenager in the early 1980s, Mahern sang lead vocals for the groundbreaking punk band, Zero Boys, using the alias Paul-Z.

Paul also started Affirmation Records to promote the hardcore punk scene in the Midwest. Unfortunately, one of the labels distributors went out of business, leaving Mahern with a slew of debts, forcing him to close the label.

Mahern continued to work as a producer and engineer on major label recordings, working in genres that extend beyond punk, including the realm of pop, and straight up rock and roll. He has worked with John Mellencamp as a producer and engineer since 1998.

In 2002, Mahern decided to reestablish Affirmation Records.