Essential Cast Additions on ‘NCIS,’ ‘SVU,’ ‘9-1-1’ & More After Series Premiere

Brian Dietzen in 'NCIS,' Kelli Giddish in 'SVU,' and Jennifer Love Hewitt in '9-1-1'
Robert Voets/CBS; Peter Kramer/NBC; FOX

Every year, there are changes to casts on our favorite shows. We have to say goodbye to character we’ve gotten to know and love over a period of time, and we might be wary of welcoming new faces into the fold. But sometimes it’s those who fall into the latter group who become essential to the DNA of a series.

In a few cases (like on NCIS and its spinoff Los Angeles), we saw these characters in a few episodes of the first season, but it wasn’t until the next that they became true permanent members. Others (like on 9-1-1Blue BloodsFBI: Most Wanted, and SVU) came in at a time when a show had lost an important character, which is never easy.

Scroll down as we take a look at some of the essential cast additions who weren’t part of our favorite shows when they originally premiered.

Jennifer Love Hewitt in '9-1-1' - 'Breaking Point'

Maddie, 9-1-1

Jennifer Love Hewitt joined the cast in the Season 2 premiere as Buck’s (Oliver Stark) sister, a nurse who would go on to fill the dispatcher hole left after Connie Britton’s exit. Since then, we’ve watched her fight to survive (successfully) her abusive ex-husband, fall in love with Chimney (Kenneth Choi), and struggle along the way, and the show just wouldn’t be the same without knowing we’ll hear her voice when someone calls for help. (Honorable mention: Ryan Guzman’s Eddie, who also joined in the Season 2 premiere).

Marisa Ramirez in 'Blue Bloods'

Baez, Blue Bloods

Marisa Ramirez came in as Danny’s (Donnie Wahlberg) partner in Season 3, following Jennifer Esposito’s exit earlier that year. Since then, some fans have wanted to see the detectives get together, and whether you’re in that group or not, you can’t deny how close the two have gotten or mean to each other. She’s even scored a coveted non-family member invite to a Reagan family dinner! (Honorable mention: Vanessa Ray’s Eddie, who joined in Season 4).

Miranda Rae Mayo as Stella Kidd in 'Chicago Fire' - Season 11
Adrian S Burrows Sr/NBC

Kidd, Chicago Fire

Miranda Rae Mayo joined the One Chicago drama in its fourth season, with the firefighter (and now lieutenant) quickly becoming a vital member of 51 and eventually the right choice to take over Truck 81 upon Matt Casey’s (Jesse Spencer) move. And while her and Severide’s (Taylor Kinney) relationship hasn’t always been easy, sparks are still flying coming up on a year after their wedding. (Honorable mention: Kara Killmer’s Brett, who joined in Season 3 following Shay’s death).

Dylan McDermott in 'FBI: Most Wanted' - 'Black Mirror'
Mark Schäfer/CBS

Remy, FBI: Most Wanted

Not only did the FBI spinoff lose its lead when Julian McMahon left, but onscreen, the Fugitive Task Force had to mourn when Jess was killed off. Dylan McDermott came in as the new team leader in Season 3 at a tough time, for the team and for fans, but he’s been a welcome addition and has seemed to fit in seamlessly, even with some understandable tension as everyone got to know each other.

Kelli Giddish in 'Law & Order: SVU' - 'And A Trauma In A Pear Tree'
Peter Kramer/NBC

Rollins, Law & Order: SVU

Kelli Giddish came in at perhaps the toughest time in SVU‘s history: in the Season 13 premiere, following Christopher Meloni’s exit. Rollins’ life was messy, she wasn’t perfect, and her relationships weren’t the greatest … until she and Carisi (Peter Scanavinofinally gave in, got together, and eventually married in what was her final episode as a series regular. The squad room hasn’t been the same since she left to teach. But the good news is she’ll be back for the Season 24 finale. (Honorable mention: Raúl Esparza’s Rafael Barba, who joined in Season 14).

Brian Dietzen in 'NCIS' - 'The Good Fighter'
Robert Voets/CBS

Palmer, NCIS

Remember when Brian Dietzen’s Jimmy Palmer was Ducky’s (David McCallum) assistant, appearing in the last three episodes of Season 1? He has come so far since then, now Dr. Jimmy Palmer, the Chief ME of NCIS, widowed, with a daughter, and much more confident than he was in those early days. And with the many cast changes over the years, he’s been a steady presence. (Honorable mention: Cote De Pablo’s Ziva, who joined in Season 3, following the death of Sasha Alexander’s Kate).

Eric Christian Olsen in 'NCIS: Los Angeles'

Deeks, NCIS: LA

Eric Christian Olsen only appeared in two episodes near the end of Season 1, eventually joining the team full-time as Kensi’s (Daniela Ruahsecond onscreen partner. (Adam Jamal Craig’s Dom went missing, then was killed just as thy found him.) It might have taken some time (and torture) for everyone to truly warm up to him, but he’s been an essential part of the team since. Plus, could you imagine NCIS: LA without watching Kensi and Deeks dance around their “thing” before eventually getting together, marrying, and bringing Rosa (Natalia Del Riego) into their family?

Jane Leeves in 'The Resident' - 'For Better or Worse'
Tom Griscom/FOX

Kit, The Resident

What would have become of Chastain and Dr. Bell (Bruce Greenwood) if Jane Leeves hadn’t joined the medical drama in Season 2? We shudder to think. The orthopedic surgeon went on to become the hospital’s badass CEO, with the best interests of its patients and staff in mind, someone important in Bell’s life as he redeemed himself even before they became involved, and eventually half a couple key to showing two people finding love again later in life.