• Miranda Cosgrove as Carly Shay, a social media influencer and the host of a comedy web series as well as Freddie's girlfriend
• Jerry Trainor as Spencer Shay, Carly's older brother, now a wealthy artist
• Nathan Kress as Freddie Benson, Carly's neighbor and technical producer for iCarly, as well as Carly's boyfriend
• Laci Mosley as Harper Bettencourt, a barista and aspiring fashion stylist who is Carly's friend and roommate
• Jaidyn Triplett as Millicent Mitchell, Freddie's adopted stepdaughter

• Lyric Lewis as Maeve (season 1), Harper's cousin who pretended to be kidnapped for four years and dates Spencer for some time
• Poppy Liu as Double Dutch (season 1; guest season 2), a pop singer who hires Harper to be her stylist^[5]
• Josh Plasse as Wes (season 1; guest season 2), a car mechanic and a former love interest of Carly
• Mary Scheer as Marissa Benson,^[6][7] Freddie's mother and Spencer's next-door neighbor. Scheer reprises her role from the original series
• Conor Husting as Beau (season 1; guest season 2), Carly's ex-boyfriend who breaks up with her at the beginning of the series
• Jeremy Rowley as Lewbert (seasons 2–3),^[8] the former doorman at Bushwell Plaza. Rowley reprises his role from the original series
• Mia Serafino as Pearl (season 2; guest season 3), an animal therapist and Freddie's ex-girlfriend
• Patty Guggenheim as Tinsley (season 3), Harper's girlfriend

• Josie Totah as Willow (season 1), an influencer who appears at Spencer's exhibit
• Alex Wassabi as an ASMR influencer (season 1), who appears at Spencer's exhibit
• Bailey Stender as Prunella (seasons 1–3), Nevel's wife
• Amanda Cerny as Harmony (season 1)
• Skye Townsend as Kiki (season 1), Millicent's scout leader in the Sunshine Girls
• Christine Taylor as Argenthina (season 1)
• Carmela Zumbado as Gwen (seasons 1 & 3), Millicent's mother, and Freddie's second ex-wife
• Esther Povitsky as Brooke (season 1), a friend of Carly and Harper's
• Tony Amendola as Vinny (season 2), a man who wants to murder Granddad Shay for stealing his coins
• Rachel Bloom as McKenna (season 2),^[9] a matchmaker
• Josh Peck as Paul (seasons 2–3),^[10] Carly's manager
• Kandy Muse as Cruella Intentions (season 2)
• Mo Heart as Auntie Histamine (season 2)
• Scarlet Envy as Lana Del Slay (season 2)
• Rosé as Kimmy Kimmy Moore (season 2)
• Hannah Stocking as Sunny, the leader of an underground fight club for influencers (season 2–3)
• Benjamin Norris as Troy (season 3), Carly's date

Then-Nickelodeon executive Paula Kaplan contacted Cosgrove with a pitch for a new iCarly series, revolving around Carly and Spencer running a Hype House-like content house with a new generation of influencers taking influence from the iCarly web show. The demographic for the show was planned to be aimed towards kids, following in the same footsteps as other revivals and spin-offs like Disney Channel's Raven's Home and Girl Meets World. "I don't think that any of us would have been up for that [idea]," she says. "What excited me about doing iCarly again was getting to put the characters in situations that we couldn't show before."^[19] Cosgrove contacted Jerry Trainor, Nathan Kress and Jennette McCurdy about the project. Kress and Trainor were on board with the project, however McCurdy declined. After multiple conversations with the returning cast, Cosgrove requested that the revival series be aimed towards the adults who grew up with it, which ViacomCBS (now Paramount Skydance) and AwesomenessTV immediately agreed to, unlike the shelved Lizzie McGuire series being developed at Disney+. As the executive producer of the series, Cosgrove wanted to incorporate more mature topics and diversity into the series, as well as nostalgia.^[19]

The series was announced in December 2020, with Jay Kogen and Ali Schouten serving as co-showrunners and executive producers. Cosgrove, Kress, and Trainor would reprise their roles from the original series.^[20][21] In February 2021, it was reported that Kogen left the project due to "creative differences" with Cosgrove, though he still retained a writing credit alongside Ali Schouten for the first episode, "iStart Over."^[22] Later that month, McCurdy confirmed that she would not reprise her role of Sam Puckett for the revival, as a result of quitting acting and feeling embarrassed by her past career.^[23] It was also revealed that the revival had been picked up for 13 episodes, with the pilot being directed by Phill Lewis, and written by Kogen and Schouten. In May, the premiere date was revealed to be June 17, 2021, with a teaser image also being revealed.^[24][6] On June 1, the first official trailer of the revival was released.^[25] On July 15, the series was renewed for a second season.^[26]

On July 27, 2022, the series was renewed for a third season, which premiered on June 1, 2023.^[27][28]

On October 4, 2023, the series was canceled after three seasons.^[4]

In March 2021, it was reported that Laci Mosley had been cast as Harper, Carly's new roommate and best friend, and that Jaidyn Triplett had been cast as Millicent, Freddie's snarky and social media-obsessed step-daughter.^[29] Since the announcement of her casting, Mosley has been the target of attacks from fans who saw her as a replacement for McCurdy's character from the original. In response, Franchesca Ramsey, one of the writers of the show, tweeted "Laci's character Harper isn't replacing Sam. No one could replace Jennette McCurdy or her incredible talent! But it's both racist as hell & completely unfair to decide that Laci hasn't earned her role especially since the show isn't even out yet!!"^[30]

In March 2021, filming for the revival had officially begun.^[29] Production on the first season ended on June 25, 2021.^[31] Production on the second season began in October 2021^[32][33] and ended on February 2, 2022.^[34]

In May 2024, Cosgrove has stated that she wants to wrap up the entire series with a finale film, confirming it would be likely, saying, "I'm pretty sure it's gonna happen, so I'm excited, and I'd love to get to wrap up the story".^[35][36] A few months later, in November, Cosgrove vaguely revealed that the project is in development.^[37]

In August 2025, Cosgrove confirmed the film was being written and that Carly and Spencer's mother will play a major role in it, but the character casting has yet to be confirmed.^{[38] [39]} Later in September, Cosgrove appeared on The Drew Barrymore Show and again confirmed that filming will begin in early 2026. It was later reported by Drew Barrymore that the film would be produced by Netflix, after speaking with Miranda.^[40]

Critics gave the first season positive reviews. On the review aggregator Rotten Tomatoes, the first season holds a 100% approval rating with an average rating of 6.7/10, based on eight reviews.