‘It’s Always Sunny in Philadelphia’ Season 18 Cast Guide: New and Returning Characters

Paddy’s Pub is back in action, and the gang has brought along both familiar faces and some unexpected guests for the ride. ‘It’s Always Sunny in Philadelphia’s‘ eighteenth season premiered on FXX and FX on August 17, 2026, featuring ten episodes. As the show enters its fifth decade on air, fans are eager to see who will be stepping through Paddy’s front door this time around.

The season stars Charlie Day, Glenn Howerton, Rob McElhenney, Kaitlin Olson, and Danny DeVito as “the Gang.” This season leans heavily into nostalgia, bringing back several beloved side characters while introducing some genuinely surprising guest appearances that have fans buzzing across social media.

Charlie Day returns as the wonderfully quirky Charlie Kelly, the former co-owner, janitor, and “rat basher” of Paddy’s Pub, who has been making fans laugh since the very first episode. In addition to starring, Day also serves as a writer and executive producer on the sitcom, and this season sees Charlie embroiled in new antics involving tent encampments, workplace automation, conspiracy theories, and even a dead woman’s inheritance.

Kaitlin Olson also reprises her role as Deandra “Sweet Dee” Reynolds, the only female member of the Gang, who remains just as hilariously toxic and self-absorbed as ever. Interestingly, Olson’s real-life husband is her co-star Rob Mac, formerly known as Rob McElhenney.

‘It’s Always Sunny in Philadelphia’ was created by Rob McElhenney, Glenn Howerton, and Charlie Day, who continue to anchor the show alongside Olson and DeVito as their antics wreak havoc on everyone around them. Danny DeVito returns as the wildly unpredictable Frank Reynolds, already at the center of one of the season’s most outrageous storylines involving his engagement to his Golden Bachelor love interest.

Season 18 also brings back several deep cuts for longtime viewers. Older characters who have been absent in recent seasons are making a comeback, including the McPoyle family, longtime rivals of the Paddy’s Pub crew, featuring Liam played by Jimmi Simpson, Ryan played by Nate Mooney, and Pappy played by Guillermo del Toro.

Also returning in their eccentric roles are David Hornsby as Rickety Cricket and Sandy Martin as Mrs. Mac. Several members of the McPoyle family reunite with the gang at the Renaissance Faire, a setting that plays a significant role in the new season’s chaos.

The del Toro cameo has particularly caught the attention of critics. His return is being hailed as one of the funniest and most unexpected cameos in any series, showcasing the show’s pitch-black humor that appeals to everyone from average viewers to Oscar-winning filmmakers. It’s a fun reminder that ‘It’s Always Sunny in Philadelphia’ has always attracted an eclectic mix of talent willing to dive into its grimiest supporting roles.

The biggest new addition to the cast is Carol Kane. Frank has found love with Sam, played by Carol Kane, whom he met while competing on ‘The Golden Bachelor’ in a crossover episode last season, and the two are set to marry at Paddy’s Pub. Much to Dennis and Dee’s delight, Sam is wealthy and generously offers to leave them money as her new stepchildren.

However, this storyline takes a dark turn. The trailer for the new season reveals the death of Kane’s character Sam, a wealthy poultry heiress and fiancée of Frank Reynolds, leading to a chaotic wedding sequence that marks a forty-year reunion for both Kane and DeVito.

In addition to returning faces, the season introduces fresh comedic cameos. The gang is joined by guest actors throughout the season, including Big Mouth comic Nick Kroll, who appears in a Renaissance Faire episode. FXX has teased that viewers should prepare for some of the series’ most outrageous moments and star cameos yet, noting that the Gang may be in their fifties and eighties now, but their behavior is more out of control than ever.

Behind the scenes, production looked a bit different this time. Season 18 was filmed in Los Angeles, including work on the Fox lot, while still utilizing Philadelphia locations and imagery to maintain its Philly setting. Reports from production indicated that Rob McElhenney and Kaitlin Olson filmed scenes in Los Angeles back in June 2026.

Managing schedules has clearly become part of the show’s reality at this stage of its run. Rob Mac has been busy with ‘Welcome to Wrexham’ and his real-life commitments running a soccer club with Ryan Reynolds, Kaitlin Olson has been starring in ‘High Potential,’ and Danny DeVito remains in demand on the big screen with projects like ‘Jumanji Open World,’ leaving Charlie Day as the only cast member with writing credits this season.

Despite everyone’s schedules pulling in different directions, the results have resonated well with critics so far. The season debuted with a 100 percent approval rating on Rotten Tomatoes. ScreenRant’s Grant Hermanns noted that although the season may not shine quite as brightly as its immediate predecessors, it still stands out among many comedies currently airing.

With the McPoyles crashing a Renaissance Faire, Guillermo del Toro making a surprise appearance, and Sam’s wedding to Frank ending in tragedy, which returning face or new cameo surprised you the most this season?