The Top 9 Greatest Casey and Severide Moments on Chicago Fire

The success of Chicago Fire is largely thanks to the strong bonds built within the walls of Firehouse 51 — especially in the case of Matthew Casey (Jesse Spencer) and Kelly Severide (Taylor Kinney). 

Casey and Severide — Chicago Fire's longtime buddy duo — have, hands down, one of the greatest friendships on the hit NBC series. The two proved how members of the same firehouse are often like family, butting heads in some episodes and then hugging in the next.

And there are hundreds, if not thousands, of touching moments between the two friends throughout their 10 shared seasons of Chicago Fire. But here are nine truly unforgettable scenes from their explosive Chicago Fire friendship.

1. Matthew Casey and Kelly Severide were always competitive

Representing both the truck (Casey) and the squad (Severide), it's no shock that the two characters frequently argued about the best course of action on a call. The constant competition kept the two friends close and prepared them for anything that they faced.

2. Matthew Casey and Kelly Severide jumped off a burning building

Season 6, Episode 11 ("Law of the Jungle")

Remember that scene where Casey ventured to the top of a burning gas building to find Severide, who was taming a leaking gas line on the roof? Remember when they both had to dive off the roof to escape a billowing explosion? The scene is one of Kinney's favorites of all time, and no one will deny: The moment sticks with fans as a classic Chicago Fire shot.

3. Matthew Casey told Kelly Severide to stand down

Season 8, Episode 16 ("The Tendency of a Drowning Victim")

After Firehouse 51 pulled a car out of a frozen lake, Casey instructed Severide to stand down after the situation was deemed a recovery mission, not a rescue mission. It was a dramatic moment that led to a tense argument between Casey and Severide. The firefighters came out stronger for the altercation after eventually reconciling. 

4. Kelly Severide stepped in to save Matthew Casey

Season 5, Episode 4 ("Nobody Else is Dying Today")

Casey became famous for literally throwing himself in the line of fire to save those who needed him most. The caveat of Casey's martyrdom was that it often got him in sticky situations, like when he compromised his safety to save a family from a toxic chemical spill.

RELATED: Jesse Spencer Returned for Chicago Fire's Season 11 Finale

Casey navigated the situation like a champ, but his work family (including Severide) was on pins and needles the entire time.

5. Matthew Casey and Kelly Severide combined forces to track down culprits

Season 8, Episode 12 ("Then Nick Porter Happened")

Through all of Casey and Severide's bickering in burning buildings, the two firefighters also came together as a powerful duo in many episodes of Chicago Fire. One of the best examples was when Casey and Severide were determined to find the culprit responsible for ringing false alarms at a school.

6. Matthew Casey confided in Kelly Severide about his kiss with Sylvie Brett

Season 9, Episode 3 ("Smash Therapy")

As competitive as Casey and Severide often got on Chicago Fire, they were also each other's best friends. There were multiple great moments of vulnerability between the two characters, usually while sharing cigars after their shift.

One of their most memorable cigar chats happened when Casey told Severide about kissing Sylvie Brett (Kara Killmer), confessing he could see a future with Brett but was fearful of moving forward. 

7. Kelly Severide and Matthew Casey's Last Call 

Season 10, Episode 5 ("Two Hundred")

After Casey announced he was leaving Firehouse 51 to move to Oregon, Severide realized he was losing his closest friend at 51. After countless fireside scrambles based on trivial misunderstandings, while Severide and Casey extinguished a church fire, it dawned on them that they were experiencing their last firefight together. It was a surreal moment for the 51 friends, who struggled with the idea of a career without the other. 

8. Matthew Casey returned to Chicago to be Kelly Severide's best man

Season 10, Episode 22 ("The Magnificent City of Chicago")

Lucky for Casey fans, his departure from the series wasn't completely permanent, thanks to several guest appearances.

Fans rejoiced when Casey returned to Chicago for the wedding between Severide and Stella Kidd (Miranda Rae Mayo). Casey arrived as Severide's best man, a fitting arrangement for the longtime pals. It was a great moment between the two friends (and also gave fans a memorable scene between Casey and Brett). 

9. Kelly Severide was Matt Casey's best man on Chicago Fire

Season 12, Episode 6 ("Port in the Storm") 

After proposing to Brett — and getting a yes — Casey named Severide as his best man.

But before the big day, Severide and Casey pulled out the cigars to kick back and relax.

"We’ve been through it, you and me," Casey reflected. "Hell and back together, more than a few times. I would be a lesser firefighter if it wasn't for that."

"I don't know what or where I'd be," Severide told Casey. "You told me once that the 'house needed me. And whether I knew it or not, I needed the 'house. I've been thinking about that a lot in the last few months."

RELATED: See Pics of Matt Casey & Sylvie Brett's Chicago Fire Wedding

"You admitting I was right?" Casey asked.

"No, I just said I thought about it, that's all," Severide teased. "It's funny how we pull out cigars, and suddenly it feels like you never left."

"In a lot of ways, I didn't," Casey responded.

"Feels permanent, somehow," Severide confessed. "When you leave this time."

"Sylvie and I will always come back to 51," Casey told his friend.

Later, Severide was beaming as he watched Casey and Brett swap their vows and begin the next chapter of their lives together. Following the ceremony, Brett and Casey headed off to Portland, with Severide cheering them on.  

Watch Chicago Fire on Peacock and NBC.