S
- Jonathan Sadowski, actor, Live Free or Die Hard
- Craig Sager, sportscaster
- Pat Sajak, television game show host Wheel of Fortune
- Jerome Sally, former NFL nose tackle
- Kiele Sanchez, actress, Married to the Kellys, Related, Lost
- Carl Sandburg, Pulitzer Prize-winning poet and journalist
- Fred Savage, actor, director, The Wonder Years, Working, Austin Powers in Goldmember
- George Schaefer, television and stage director
- Lanny D. Schmidt, chemist, inventor, author, and professor
- Bill Schulz, regular panelist, writer, and producer on Fox News Channel's Red Eye w/ Greg Gutfeld
- William Schutz, psychologist
- Rusty Schwimmer, actress, Twister, The Perfect Storm
- Edward Willis Scripps, newspaper publisher, founder of E.W. Scripps Company
- Richard Warren Sears, businessman, co-founder of Sears, Roebuck and Company
- Kevin Seitzer, former All-Star MLB third baseman and current hitting coach for the Kansas City Royals
- Michael Shannon, actor, Boardwalk Empire, Pearl Harbor, Bad Boys II
- Shannon Sharpe, Hall of Fame NFL tight end
- Sterling Sharpe, former wide receiver for the Green Bay Packers, analyst for the NFL Network
- Bernard J. Sheil, Roman Catholic Archbishop and founder of the Catholic Youth Organization
- Derek Shelton, hitting coach for the Tampa Bay Rays
- Sam Shepard, actor, director and Pulitzer Prize winning playwright, Black Hawk Down, The Pelican Brief, The Right Stuff
- Sherri Shepherd, comedienne, actress, co-host of The View
- Brian Sherwin, art critic, curator, writer.
- Kiernan Shipka, child actress, Sally Draper on Mad Men
- William Shockley, (1910–1989), Nobel Prize-winning physicist and co-inventor of the transistor
- Bobby Short, cabaret singer and performer
- Brian Shouse, former MLB relief pitcher
- Iman Shumpert, guard for the New York Knicks
- Casey Siemaszko, actor, NYPD Blue, Back to the Future parts 1 and 2
- Shel Silverstein, cartoonist, screenwriter and author of children's books
- Bobby Simmons, small forward/shooting guard for the Los Angeles Clippers
- James Singleton, power forward for the Guangdong Southern Tigers
- Gary Sinise, Golden Globe and Emmy Award winning actor, director and musician CSI: NY, Forrest Gump, Apollo 13
- Gene Siskel, television journalist, film critic and author
- Jeffrey Skilling, former president of Enron, convicted of multiple federal felony charges
- Tom Skilling, meteorologist for WGN News
- Bill "Moose" Skowron, MLB first baseman, primarily with the New York Yankees
- Duke Slater, NFL tackle and College Football Hall of Famer
- John Slater, physicist
- Jerry Sloan, HOF former head coach and former NBA All-Star player for the Chicago Bulls
- Albion W. Small, sociologist and university professor
- Art Smith, actor
- Joseph Smith, Jr., prophet and founder of the Latter Day Saint movement
- Kellita Smith, actress and model, The Bernie Mac Show
- Lonnie Smith, former Major League Baseball outfielder
- Sandra Smith, Business news reporter for the Fox Business Network
- Carrie Snodgress, actress
- Rafael Sorkin, physicist
- David Soul, actor and singer, Starsky and Hutch, Here Come the Brides, The Yellow Rose
- Soulja Boy, rapper
- John Spalding, Roman Catholic Bishop and co-founder of The Catholic University of America
- Richard Speck, mass murderer
- Mac Speedie, wide receiver for the Cleveland Browns and head coach for the Denver Broncos
- Donald Spero, rower
- Lawrence Sperry, aviation pioneer
- Anthony Spilotro, mobster and enforcer for the Chicago Outfit
- Erik Spoelstra, head coach for the Miami Heat
- Jimmy Stafford, lead guitarist for Train
- Amos Alonzo Stagg, College Hall of Fame football coach and athlete, creator of the lateral pass and helmet
- Michael Stahl-David, actor, The Black Donnellys
- Dino Stamatopoulos, television comedy writer, actor, producer
- Ellen Gates Starr, social reformer and co-founder of Hull House
- Todd Stashwick, actor, The Riches
- Shelby Steele, columnist, documentary filmmaker, author of White Guilt
- James R. Stein, TV writer and producer, America 2-Night, Fernwood 2 Night, Son of the Beach
- Rick Stelmaszek, former MLB catcher and current bullpen coach for the Minnesota Twins
- Fisher Stevens, actor, producer, director, Early Edition, Key West
- John Paul Stevens, attorney, jurist, Supreme Court Justice
- Adlai Stevenson II, attorney, politician (Democrat), Illinois Governor, Ambassador to the United Nations, Presidential candidate in 1952 and 1956
- David Ogden Stiers, actor and orchestral conductor; M*A*S*H, The Dead Zone, Better Off Dead
- James Stockdale, one of the most highly decorated officers in the history of the United States Navy, 1992 candidate for Vice President of the United States
- Dejan Stojanović, poet, writer, essayist, philosopher, businessman, and former journalist
- Melville E. Stone, newspaper publisher and manager of the Associated Press
- Lauren Storm, actress, Flight 29 Down
- John Stossel, consumer reporter, investigative journalist, author
- Michael Stoyanov, actor, TV comedy writer, Blossom
- The Brothers Strause, directing duo, special effects artists
- Barbara Stuart, television actress
- Patrick Stump, lead singer of the band Fall Out Boy
- Louis Sullivan, architect
- Daniel Sunjata, actor, Rescue Me, Law & Order: Special Victims Unit, The Devil Wears Prada
- Lynn Sweet, Washington D.C. bureau chief for the Chicago Sun-Times, columnist for The Hill
- Gustavus Franklin Swift, inventor, meat-packing entrepreneur
- Keith Szarabajka, actor, The Dark Knight, We Were Soldiers, The Equalizer
Read more about this topic: List Of People From Illinois