On its website, the Chicago Sinfonietta calls itself "a defiantly different kind of orchestra." Established by pioneering African-American conductor Paul Freeman, the orchestra has had the goal of performing music accessible to various constituencies, with a specialty in rarely heard music by composers of color.

The orchestra was founded in 1987 by Freeman, who eventually became the first African-American conductor of more than 50 orchestras worldwide but had difficulty finding a permanent conducting position. (He eventually became conductor of the Czech National Orchestra.) From the beginning, the group toured widely, in Europe and other overseas destinations as well as in the U.S. They have toured Europe six times and performed twice at New York's Kennedy Center. At home in Chicago, where it has performed at Orchestra Hall, the Harris Theater, and the Wentz Concert Hall at North Central College in nearby Naperville, the group welcomed a large variety of guests from both within and beyond the traditional classical spheres. In the orchestra's first decade, those guests included the Vienna Boys' Choir, pop vocalist Ben Vereen, and jazz pianist Marian McPartland; later guests included the rock group Poi Dog Pondering, Chicago violinist Rachel Barton Pine, and the Apostolic Church of God Choir. Concerts have included such unusual instruments as bagpipes, steel drums, hip-hop electronics, and even cell phones. Freeman retired in 2011 and Taiwanese-born conductor Mei-Ann Chen was hired to become the Sinfonietta's second conductor, beginning with the 2011-2012 season.

Beginning with the Shostakovich Film Festival album in 1991, the orchestra has recorded mostly unfamiliar classical repertory. Freeman conducted the group in a two-volume African Symphonic Heritage Series for Chicago's Cedille label in the early 2000s, as well as in an album (with pianist Derek Han) of works by Edward MacDowell. Chen has continued the orchestra's recording program on Cedille; in 2019 she and the orchestra issued Project W, an album of works by "Diverse Women Composers." ~ James Manheim, Rovi