After two episodes aired, Fox renewed 9-1-1 (2018) for a second season, announced on January 16, 2018.

One episode begins with a wedding party that ended in a catastrophic building collapse where the floor gave out under the weight of all of the party goers. This is based on an actual event that occurred in Israel where 24 people lost their lives as a result of a floor giving out due to poor or improper building materials used during construction.

Oliver Stark was considering quitting acting and becoming a firefighter before getting cast as one on 9-1-1 (2018).

Both Angela Bassett and Aisha Hinds have portrayed Voletta Wallace, the mother of The Notorious B.I.G.: Bassett in the film Notorious (2009) and Hinds in the limited series Unsolved (2018).

Rockmond Dunbar and Kenneth Choi appeared on Sons of Anarchy (2008) together. Dunbar played the new Sheriff in Charming and Choi played Chinese gangster Henry Lin.

Angela Bassett and Connie Britton both appeared on Ameerika õudukas (2011).

Athena Grant's badge number is 1275, a reference to I-275, the freeway that runs through Angela Bassett's hometown of St. Petersburg, Florida. Grant's unit number is 727-L-30; 727 is St. Petersburg's telephone area code.

Oliver Stark confirmed via Twitter on January 31, 2018, that despite being ordered for a 13-episode first season, 9-1-1 (2018)'s season one will have only 10 episodes.

Connie Britton and Kenneth Choi both appeared in American Crime Story (2016): The People v. O.J. Simpson with Courtney B. Vance, who is married to 9-1-1 (2018) co-star Angela Bassett.

In episode two, Hen invites Athena to the fire station and tells the crew that she has family issues and needs some TLC (Tender Loving Care). In the same episode, TLC's No scrubs can be listened to while Athena drives her patrol. Another time, Athena tells Buck not to go chasing Waterfalls, a clear reference to TLC's Waterfalls.

First broadcast on italian TV will be on January 9th 2019 (9-1-19), a palindrome of 9-1-1.