Painter, printmaker, and educator Paul Brach was born in New York City on March 13, 1924. In his early life he worked summers as a ranch hand, which would influence the feel of his work throughout his career. He attended the University of Iowa, interrupted in his studies by the draft during World War II before returning to complete his studies on the GI Bill. While there, he studied under celebrated printmaking teacher Mauricio Lasansky. It was in these classes that he met the artist Miriam Schapiro; they wed in 1946, and in 1951 they returned to Manhattan.

Soon after their arrival in New York Brach and Schapiro became a part of the burgeoning New York School of the Abstract Expressionist scene, alongside Joan Mitchell, Philip Guston, Larry Rivers, Knox Martin, and several others. After forming a friendship with artist and future gallerist Leo Castelli, he helped him design and open a gallery in the bottom floor of Castelli's home; the Leo Castelli Gallery continues to be a primary exhibition space in Manhattan today.

At this time Brach also immersed himself in experiemental printmaking at Atelier 17 under Stanley William Hayter, who had relocated his famed Paris studio to New York with the onset of the war. By the late 1950s he began to break away of Abstract Expressionism to move toward Minimalism, using an often monochromatic palette and energetic linework.

In the early 1960s Brach began his long and prolific career in teaching, taking posts at The New School, Cooper Union, the Parsons School of Design, and the New York City program of Cornell University. In 1967, he was offered the position of art department chair at the University of California, San Diego. He and Schapiro moved across the country and settled in San Diego for two years, at which time Brach co-founded the California Institute of the Arts in Santa Clarita. He helped to establish the school's reputation as the first fully arts-based school to grant traditional degrees. It quickly became a magnet for performance and visual arts students across the U.S., hosting such luminaries as John Baldessari, Allan Kaprow, Max Kozloff, and others. Brach remained dean of the school until 1975, when he and Schapiro decided to return to the East Coast.

Brach's work now began to focus more and more on figurative and landscape subjects, with particular focus on Western scenes that still retained his Minimalist style. The call to art eventually outweighed his desire to teach, and after several years as the chair of the Division of the Arts at Fordham University in New York, he retired from teaching to focus on painting. He worked throughout the late 1980s and '90s in New York, and was elected into the National Academy of Design in 1997. In 1998, the couple relocated permanently to East Hampton, where Brach set up a studio and continued to work until his death on November 16, 2007.

Brach exhibited at the Leo Castelli Gallery, the Cordier & Eckstrom Gallery, and the Andre Emmerich Gallery, among others. He was awarded the Distinguished Teaching of Art Award by the College Art Association in 1994.