Title: Chicago Fire (season 4)
Content:  The fourth season of Chicago Fire, an American drama television series with executive producer Dick Wolf, and producers Derek Haas, Michael Brandt, and Matt Olmstead, was ordered on February 5, 2015, by NBC, and premiered on October 13, 2015, and concluded on May 17, 2016. The season contained 23 episodes.
Title: Chicago Fire (season 4)
Content: Jesse Spencer as Lieutenant Matthew Casey, Truck 81 ; Taylor Kinney as Firefighter/Lieutenant Kelly Severide, Squad 3 ; Monica Raymund as Firefighter Gabriela Dawson, Truck 81 ; Kara Killmer as Paramedic/Paramedic In Charge Sylvie Brett, Ambulance 61 ; David Eigenberg as Firefighter Christopher Herrmann, Truck 81 ; Yuri Sardarov as Firefighter Brian "Otis" Zvonecek, Truck 81 ; Joe Minoso as Firefighter Joe Cruz, Squad 3 ; Christian Stolte as Firefighter Randy "Mouch" McHolland, Truck 81 ; Dora Madison as Paramedic in Charge/Paramedic Jessica "Chili" Chilton, Ambulance 61 (Episodes 1-14) ; Steven R. McQueen as Firefighter Candidate/Paramedic Jimmy Borelli, Truck 81/ Ambulance 61 ; Eamonn Walker as Chief Wallace Boden, Battalion 25 
Title: Chicago Fire (season 4)
Content:  The show follows the lives of the firefighters and paramedics working at the Chicago Fire Department at the firehouse of Engine 51, Truck 81, Squad 3, Ambulance 61 and Battalion 25.
Title: Chicago Fire (TV series)
Content:  Chicago Fire had its episode total increased from 22 to 23. One week later, on February 6, 2013, Chicago Fire received one more episode, giving it a total of 24 episodes for season one. The pilot episode had an early release at NBC.com, before the series' premiere on television. On November 9, 2015, NBC renewed the series for a fifth season. The season premiered on October 11, 2016. On May 9, 2018, NBC renewed the series for a seventh season, which premiered on September 26, 2018. On February 26, 2019, NBC renewed the series for an eighth season, which premiered on September 25, 2019. In February 2020, the series was renewed for a ninth, tenth and eleventh season.
Title: List of Chicago Fire episodes
Content:  Chicago Fire is an American television drama created by Michael Brandt and Derek Haas, who serve as executive producers alongside Joe Chappelle, Peter Jankowski, Danielle Gelber, Matt Olmstead and Dick Wolf. The series, which premiered on October 10, 2012, airs on NBC. The series follows the lives of the firefighters and paramedics working at the Chicago Fire Department at the firehouse of Engine Company 51, Truck Company 81, Rescue Squad Company 3, Ambulance 61 and Battalion 25, starring Jesse Spencer as Lieutenant Matthew Casey, Taylor Kinney as Lieutenant Kelly Severide, Yuri Sardarov as firefighter Brian "Otis" Zvonecek who left after the eighth-season premiere, Charlie Barnett as Firefighter Candidate Peter Mills, who left the series in the third-season episode "You Know Where To Find Me", Monica Raymund as Paramedic in Charge Gabriela Dawson, who left in the seventh season premiere, Lauren German as Paramedic Leslie Elizabeth Shay, who left after the third-season premiere, Eamonn Walker as 25th Battalion Chief Wallace Boden, David Eigenberg as firefighter Christopher Herrmann, and Teri Reeves as Doctor Hallie Thomas. Other characters joined the series in later seasons. The tenth season premiered on September 22, 2021.
Title: Chicago Fire (TV series)
Content:  Chicago Fire is broadcast by NBC in the United States. The latest five episodes of Chicago Fire are available on Hulu with a subscription. Season 4 is available on NBC.com and the NBC app with a cable subscription. All episodes are available from electronic sell-through platforms such as iTunes, Amazon Instant Video, and Vudu. The series will be available for streaming on Peacock along with Chicago P.D., Chicago Med, Law & Order, Law & Order: Special Victims Unit and Law & Order: Criminal Intent. In Canada, the series aired on Global for seven seasons, then moved to CityTV.
Title: Chicago P.D. (season 4)
Content:  The fourth season of Chicago P.D., an American police drama television series with executive producer Dick Wolf, and producers Derek Haas, Michael Brandt, and Matt Olmstead, premiered September 21, 2016 and concluded on May 17, 2017. The season contained 23 episodes.
Title: Chicago Fire (season 4)
Content: The Cohen Twins (Aiden & Austin Cohen) as Louie ; Randy Flagler as Firefighter Harold Capp, Rescue Squad 3 ; Anthony Ferraris as Firefighter Tony Ferraris, Rescue Squad 3 ; DuShon Brown as Connie ; Brian J. White as Captain/Battalion Chief Dallas Patterson, Rescue Squad 3/ Firehouse 51/ Firehouse 90 ; Miranda Rae Mayo as Firefighter Stella Kidd, Truck 81 ; Treat Williams as Benjamin "Benny" Severide ; Melissa Ponzio as Donna Robbins-Boden ; Robyn Coffin as Cindy Herrmann ; Brandon Jay McLaren as Danny Booker ; Jenny Mollen as Detective Bianca Holloway ; Holly Robinson Peete as Tamara Jones ; Lauren Stamile as Susan Weller ; Guy Burnet as Grant Smith ; Gordon Clapp as Chaplain Orlovsky ; Liza J. Bennett as Agent Alex Ward ; Deanna Reed-Foster as Tina Cantrell ; Rachel Nichols as Jamie Killian ; Fredric Lehne as Deputy District Chief Ray Riddle ; Tom Amandes as Detective Ryan Wheeler ; Ilfenesh Hadera as Serena Holmes ; Mark Hengst as Roger Maddox ; Ralph Rodriguez as Freddie Clemente ; Susannah Flood as Athena Bailey-Johnson ; Andy Ahrens as Firefighter Danny Borelli, Engine 67 ; Eric Mabius as Jack Nesbitt 
Title: Chicago P.D. (season 4)
Content:  A crossover starting on Chicago Fire and concluding on Chicago PD aired on January 3, 2017. A three-way crossover between Chicago Fire, Chicago PD and the premiere of Chicago Justice aired on March 1, 2017, with heavy involvement from Chicago Med.
Title: Chicago Fire (season 5)
Content:  The fifth season of Chicago Fire, an American drama television series with executive producer Dick Wolf, and producers Derek Haas, Michael Brandt, and Matt Olmstead, was ordered on November 9, 2015, by NBC. The eighth Episode “ONE HUNDRED” is The Shows 100th EPISODE’ The Episode also served as the FALL FINALE The season premiered on October 11, 2016 and contained 22 episodes. The season concluded on May 16, 2017.

Question: how many episodes are in chicago fire season 4?
Answer: 23.