Lasansky was also a teacher for most of his life—first in his native Argentina and later in Iowa where he lived for more than 65 years. At the University of Iowa in Iowa City, he developed a printmaking workshop that was ranked among the very best in the world. In 1966, Time magazine called Lasansky "the nation's most influential printmaker." During his tenure, he had the opportunity to disseminate his extensive knowledge of printmaking processes to generations of students, many of whom went on to become successful artists and professors themselves. Lasansky’s legacy as an artist-educator figures prominently in what has become known as the post-World War II renaissance of American printmaking.

Lasansky is also known worldwide for works of art that examine the brutality of Nazi Germany. Best known are The Nazi Drawings, a powerful expression of the profound disgust and outrage Lasansky felt after viewing a US Military documentary showing the victims and aftermath of Nazi atrocities. Lasansky worked intensively for six years to create the series, which consists of thirty individual pieces and one triptych. The drawings were created with pencil, water- and turpentine-based washes, and collage on common commercial paper. Since their completion in the late 1960's, The Nazi Drawings have been exhibited in many prominent art museums, and have received widespread public attention. In 1967, The Nazi Drawings, along with shows by Louise Nevelson and Andrew Wyeth, were the first exhibits installed at the new Whitney Museum of American Art in New York City. The series will be featured at the Minnesota Institute of Art in late 2020.

Courtesy Lasansky Art