Gerson August Leiber was born in Brooklyn, New York in 1921. He showed an early aptitiude in art, but before he could enroll in college he was drafted into the Army during World War II and stationed in Hungary. While there, he met master craftswoman Judit (later Judith) Petö, who encouraged him to enroll in classes at the Royal Academy of Art in Budapest. They would marry in 1946 before moving to New York in 1947.

Once settled, Leiber enrolled in courses at the Art Students League, studying printmaking under Will Barnett, and at the Brooklyn Museum's art school, where he studied engraving Gabor Peterdi. His prints were featured in various one-man shows, including exhibitions at Associated American Artists and the Alex Rosenberg Gallery. In the 1950s he began pursuing painting with more frequency but continued to make and exhibit prints. He taught etching and engraving at the Printmaking Workshop established by Robert Blackburn.

In the 1960s, Gerson persuaded his wife, by now a sought-after handbag designer with high profile clients, to produce her work independently, and they started their own business based on her designs. They bought a farmhouse in East Hampton, Long Island, intended as a summer cottage but eventually becoming their permanent residence. They would later also open a gallery and museum that showcased their work and chronicaled their extensive collaborative career. Inspired by his surroundings like his garden, nature, and fashion, Gerson painted nearly every day as he had done since his high school years.

Leiber exhibited at the Denise Bibro Fine Art in 2002; Steinbaum-Krauss Galleries in 1998; Longue Vue Gardnes in 1997; Kennedy Galleries in 1996; Arlene Bujese Galleries in 19915; Israel Museum in 1994; Fine Arts Museum of Long Island in 1991; Vered Galleries in 1985; Alex Rosenberg Gallery in 1985; Print Club of Philadelphia; Society of American Graphic Artists; New Britain Art Museum; Brooklyn Museum; Pennsylvania Academy of Fine Arts; Audubon Artist; Matrix Gallery; Bay Printmaker's Society Exhibition; Oakland Museum; Associated American Artists.

Both Leiber and Judith died on April 28, 2018, two hours apart.