Mieczkowski is an important part of both Cleveland and New York's art scene. The artist taught at the Cleveland Institute of Art for 39 years whilst also working in his New York based studio. Today, Mieczkowski lives and works in Huntington Beach, CA.

As well as awards and teaching, Mieczkowski was a founding member of the American art group, Anonima, which was active from 1960 to 1971. The group's experimentation with perceptual abstraction were a precursor for the the Op Art movement.

A painting by Mieczkowski was included in the 1964 Time magazine article that introduced Op Art to the public. As well as this, the inclusion of his work in The Responsive Eye exhibition at the MoMA, New York City, in 1965 cemented his importance as an artist as the forefront of the Op Art movement.