- The life of the Nuclear Family in "Nuclear Family Values": they were made to show the effects of Nuclear warfare and instead, they are built so well that they not only survived, they got powers from it. However, they had to keep hiding in areas where they could thrive in. Even Firestorm didn't have the heart to destroy them, so he gave them their own little home.
- Shazam in "Shazam Slam" is really worried about Billy, who's being held hostage by Black Adam. Given his backstory, you can only imagine how he is feeling right now; he's got an orphan child to be in the midsts of watching his world get destroyed. If Billy wasn't The Pollyanna of the DCU, I think that would have gone a lot worse.
- How sad Killer Frost was after Mr. Freeze double-crosses her in "Freezer Burn". She even sadly laments to 'Never meet your Idols'.
- In "Repulse", Superman is willing to go into a Black Hole so that no one can get hurt by the Nanobots...especially since they've attached to him and made him into a threat to others.
- "Time Out" begins with Batman angrily berating Booster Gold for botching a mission because he got distracted, culminating in him calling Booster the worst crime fighter he's ever known. Bats quickly eats his words when he and Booster are caught in a time fissure together, and Bats figures out what Booster does in his spare time. Rather than goofing off like Bats assumes he does, Booster is constantly maintaining the time stream, and never once mentioning it because he doesn't think it's that big of a deal. Booster ends up having to send Bats back to the present in order to defeat the Monster of the Week, but doing so would wipe Bats' memories of everything that's happened between them, while Booster will remember it. After the threat is defeated and the time stream is fixed, Booster goes right back to being berated by Batman. The episode ends with Booster telling Batman he's right about him being a terrible crime fighter, and Batman storming off. Wonder Woman asks Bats if maybe he was too hard on Booster, but Batman assures her it's what Booster needs to hear. Booster just floats away, sad and dejected...but with a memento of their adventure together before Batman forgot.
- "Plastic Man Saves the World" had Plastic Man on board Brainiac's ship when it explodes, and everyone is shocked, then saddened when they realize he might have just done a Heroic Sacrifice. Even Superman has a Humble Pie moment when he admits to Batman that Plastic Man really DID deserve to have been in the Justice League after all (as earlier Superman wasn't sure he wanted Plastic man to stay). But then Plastic Man floats down with all the bottle cities he could get off of the ship before it did explode...
- "System Error"'s climax sees the robot League be at peace with the fact that the pocket dimension they were in was collapsing, knowing they stopped Darkseid. Granted, the real Batman managed to save them, but until then, they were willing sacrifice themselves and accept death knowing they stopped a monster at the possible cost of their lives.
- One of the happiest iterations of a Tear Jerking Moment is that Aya is alive. It's unknown whether or not Justice League Action takes place in the same continuity as Green Lantern: The Animated Series, however, Aya's memories of her time with her team start to resurface, and she parts ways with Space Cabbie to find her someone.
- In "She Wore Red Velvet", It's revealed that the reason Booster Gold is always trying to get rich is because before he went back in time, Booster had hit the lowest point in his life, but eventually, he met an heiress named Margot, and the two fell in love. But on their wedding day, he realized that he could never support her by himself, so he excused himself during the ceremony and traveled through time, planning on returning when he made enough money.
- Also, the team is led to believe that reason Red Velvet/Margot is mad at Booster is because he left her at the altar until it turns out the real reason she's mad at him is because it's the exact opposite. Booster would eventually return, but he turns out to be a terrible husband. The predicament itself is then reversed when Margo refuses to marry Booster after listening to her future self.
Tear Jerker / Justice League Action