Casimir Nierzwicki, 73, of Rockford, Illinois, passed away peacefully on June 30, surrounded by his family.

Casimir was born on February 14, 1953, in Poland to Jozef and Anzelma (Mazela) Nierzwicki and later immigrated to America as a young boy. As a young man, he was an adventurer who enjoyed exploring the open roads on his motorcycle. On May 17, 1985, he set down his bike to marry Elizabeth Malinowska and start a family. Casimir was blessed with three boys and was a devoted father and husband. He worked at GKN (formerly Rockford Clutch and Rockford Powertrain) as a skilled machinist for more than 45 years until he retired. Casimir enjoyed spending time with his family (especially his grandchildren), reading and watching both history and science fiction, and rooting for the Chicago Cubs and Chicago Bears. Casimir will be especially remembered for his quick-witted sense of humor, his selfless and hardworking nature, and for his strong Catholic faith.

Casimir is survived and dearly missed by his devoted wife of 41 years, Elizabeth; sons, David (Miranda), Paul, Patrick (Rachel); beloved grandchildren, Miles and Simon; sister, Stephanie Drahn; niece, Sonia Hoglund; family friend, Spencer Hill; and many cousins.

He was preceded in death by his parents, Jozef and Anzelma; uncles, Franciszek Nierzwicki and Franciszek Mazela.

A visitation will take place on Monday, July 6, 2026, from 4:00 p.m. until 5:00 p.m. at Fitzgerald Funeral Home, Mulford Chapel, 1860 S. Mulford Road, Rockford, IL, 61108. Funeral Mass will take place the following day, Tuesday, July 7, 2026, at 10:00 a.m. at Holy Family Catholic Church, 4401 Highcrest Rd, Rockford, IL 61107. Burial at Calvary Catholic Cemetery. To share memories and condolences online, please visit www.fitzgeraldfh.com.

The family extends a heartfelt thank you to the staff of OSF Hospice, especially Brittany, Bridgette, Patrina, and Darren.