Upon finishing high school, Bart Sears attended the Joe Kubert School of Cartooning and Graphic Arts. After graduating from the Kubert school in the early-80s Bart lent his unique style to the toy industry, pencilling the mini-comic that came packaged with the "Sectaurs" action figure line from Coleco Toys. He worked on the GI Joe toy line and did the character design work for the Hasbro C.O.P.S. action figures. In addition, Bart was the penciller for the DC comics Cops monthly series. He also worked in the role-playing game genre, providing artwork for several TSR products.

Bart provided covers and fill-ins for several titles early in his comcis career, including many covers for Quality comics and interiors for DC comics Spectre number 22. He made his biggest early impact on the comic book industry as the penciller of DC's Justice League Europe series, providing the pencils for 22 issues. His other notable runs included stints on Valiants X-O Manowar and two seperate runs on Turok, Dinosaur Hunter.

Sears is also widely known for his monthly "Brutes and Babes" feature in early issues of Wizard magazine. The series of over 30 comic art tutorials was highly regarded as a helpful tool and primer for aspiring industry professionals. Bart's gift for instruction and knowledge of the craft also led him to return to the Kubert school as an instructor for a short time.

In the mid-90s Sears also continued to work in the toy design field, providing several designs for the Hasbro World Wrestling Federation line and the best of Toybiz's early X-Men action figure series. Around the time of his work on the X-Men line Sears also formed his own comics company, which did not last and only produced a handful of comics. After that Bart took several freelance jobs, including work for the adult-oriented Penthouse Comix, before settling in at Marvel. Bart did numerous fill-in issues for the company and worked as regular penciller on the short-lived Spider-Woman series with writer John Byrne. Sears soon left Marvel and went to work for Crossgen comics. There he would work as a penciller and behind the scenes as art director for the company. When Crossgen went under Bart returned to freelance work, including work for DC comics 2005 Warlord series.