Following graduation from the University of New Hampshire with a degree in Painting and Graphics, Peter Mallen embarked on his journey of artistic pursuit that continues to this day. In addition to his fine art focus, he has a successful career as a scientific illustrator working with medical research scientists. For many years he was affiliated with the Schepens Eye Research Institute, Harvard Medical School. Mallen's work has been exhibited in galleries and museums worldwide. His art is included in the collections of The Historic New Orleans Collection, The College Book Art Association. His Artist's Books are included in the Museum of Modern Art / Franklin Furnace / Artists' Books Collection.

Currently focused on painting, prints and sculpture, Mallen is producing large scale paintings, color woodcuts and stone sculpture. In May, 2017, he was an International Artist in Residence at the UNESCO Medina of Tetouan, Morocco, focusing on the native endangered species of that country. In  2019, he was the Artist in Residence at ArtKlub NOLA, where his residency project focused on the 1973 UpStairs Lounge tragedy, the largest mass-murder of LGTBQ+ until the Pulse Nightclub. His work has recently been included in an international woodcut exhibitions in Kyoto and Tokoshima, as well as a solo show in Provincetown, and at Out of the Blue Gallery in Cambridge, MA.

In collaboration with fellow artist, Harry Judd, Mallen also produces and mounts street installation projects focusing on social justice issues. In July, 2016, they created ArtAttack/Oak Bluffs in response to the mass-murder attack at the Pulse Nightclub in Orlando (51 pieces installed in Oak Bluffs Arts District). During Women's Week in October, 2016, Judd and Mallen installed ArtAttack/Provincetown which focused on gender equity and pay parity (45 pieces installed in Provincetown's East End Gallery District). In each case, the surviving art works were donated to a charity. The Oak Bluffs pieces went to the town library, while the Provincetown pieces went to Helping Our Women (HOW). The pair installed ArtAttacks in New Orleans (February-March), San Diego (March-April) Paris (September).

Mallen will be exhibiting from his west coast studio, while continuing to work in his summer studio in Cohasset, Massachusetts.