Scott Edward Harris Lang is a former convicted thief who struggled to pay child support to his estranged wife with whom he had a daughter, Cassie Lang. With the promise of money, he was convinced by Hank Pym to take on the mantle of Ant-Man, a superhero with an advanced suit designed to shrink its wearer to a tiny size while increasing one's toughness, agility, and physical strength. Trained under Pym and his daughter Hope van Dyne, Ant-Man was to help foil Pym's former protege Darren Cross, who was intending to sell his Yellowjacket Suit design and his copy of the Pym Particles formula to Hydra and the Ten Rings. However, their plan was discovered by Cross, culminating in a final fight between Yellowjacket and Ant-Man. To defeat him, Ant-Man shrunk small enough to enter Yellowjacket's suit and destroy it, sending Ant-Man to the Quantum Realm, but he was able to escape. Ant-Man's heroism helped restore his relationship with Cassie and his ex-wife, as well as find a new romantic one with van Dyne. Lang soon learned that the Avengers were seeking for his help
Against Pym and van Dyne's wishes, Ant-Man joined Captain America's side during the Avengers Civil War, having been recommended by the Falcon following their previous encounter. Ant-Man fought against Iron Man and his allies, allowing Captain America and Winter Soldier to escape. Ant-Man and several of his new allies were then arrested and imprisoned in the Raft by Thaddeus Ross. When Captain America arrived to free them, Ant-Man escaped, but later made a deal with the FBI to be put under house arrest so that he could still spend time with his family
Three days before Lang could finish his sentence, he had a strange vision of Janet van Dyne, who had remained trapped inside the Quantum Realm, and with whom Lang became psychically entangled with while he was there. This resulted in Lang being kidnapped by Pym and Hope van Dyne, who had built a Quantum Tunnel machine and intended to use it and Ant-Man to rescue Janet. These plans went awry when Ant-Man and Wasp were confronted by both Ghost and Sonny Burch, who wanted to steal the Quantum Tunnel machine for their own reasons. Ant-Man, Wasp, and Pym eventually succeeded in rescuing Janet from the Quantum Realm. Ant-Man was then able to return home just in time to finish his house arrest, narrowly avoiding an extended prison sentence for violating the terms
However, during a trip to the Quantum Realm to gather quantum particles for Ghost, Ant-Man became trapped as Pym's entire family was turned to dust by Thanos. Ant-Man was unable to escape until 2023, where he regrouped with the Avengers and, realizing that time flowed differently in the Quantum Realm since he only experienced five hours while trapped, suggested that they use the Quantum Realm as a means of time travel to the past. Ant-Man then officially joined the Avengers and participated in the Time Heist, where they successfully managed to acquire the six Infinity Stones from alternate pasts and used the Stones to resurrect the victims of Thanos' Snap. However, an alternate Thanos had managed to follow the Avengers through time, and Ant-Man fought in the resulting Battle of Earth. Thanos and his army were eventually destroyed, after which Lang celebrated the victory with van Dyne and Cassie, and attended Tony Stark's funeral
