In her childhood, Bull frequented the Newark Museum of Art in New Jersey to study. Bull next expanded her studies into painting when she attended Bennington College, headed at the time by artist Paul Freely, where she graduated with a B.A. in Music and Art in 1960. In 1969, she married painter Malcolm Morley. The marriage lasted until their divorce in 1972, yet his pieces would go on to influence her earliest works. She would then attend New York University, where she graduated in 1980 with an M.A. degree in Art and Art Education.
Bull became known originally for her Photorealism paintings made in the mid 1970s and 80s. Among her most famous Photorealist works are Flamingo Stereopticon, Lincoln Center Reclining Figure and Winged Narcissus. This earlier work was influenced by her mentor and ex-husband, Malcolm Morley and by the Pop spirit of Photorealism. It was shown and sold through the Louis K. Meisel Gallery in New York City and has been collected widely in Kansas City through the Morgan Gallery, owned before her death by curator and gallerist Myra Morgan. During this time, Bull was one of the most noted photo-realists along with Morley.