Wally West is the fastest man alive, and the second speedster known as the Flash. Using his super-speed powers, he wields the Speed Force and becomes a costumed crime-fighter. He is a founding member of the Teen Titans.
After Wally's accident, he then became the Flash's sidekick, and would become known as Kid Flash.
Wally West, was known as Kid Flash, currently known as The Flash, was acting as the partner to Barry Allen's The Flash, when at the age of 15, he was invited to join the Justice League. However he learned, alongside the other sidekicks, that full membership into the League was not on the table. They would only be given access to the League's public office and not the actual headquarters.
He joined Aqualad, Robin, and Speedy on July 4th in entering the Hall of Justice after having defeated Captain Cold with Flash. While the League was dealing with other matters, Aqualad, Kid Flash, and Robin investigated a fire at Project Cadmus. Together they rescued a clone of Superman, known as the Super Boy, and with his assistance, defeated a mutated Mark Desmond. In an act of defiance, the four teens banded together to form a team, and on July 8th they were brought to the Secret Sanctuary, where they met their fifth member, Miss Martian.
When the team was confronted by Mister Twister, Miss Martian posed as Red Tornado using Kid Flash to generate twisters. When she crushed the android within the battle suit, Kid Flash took the inner android's eye as a souvenir, the beginning of a tradition. During the team's first official mission, Kid Flash questioned Robin's abilities as a leader. After some hesitation, he agreed with the team and accepted Aqualad as his leader.
Later, Wally was introduced to the sixth member of the team, Artemis. The two, however, did not get along, not even on missions. The rift between them was so that in the episode "Infiltrator", when Miss Martian and Artemis were caught off guard by while protecting Dr. Roquettefrom the League of Shadows, Wally placed all blame on Artemis even though both women were equally at fault.
Friction between Artemis and Kid Flash increased during the team's next mission when they went to rescue Kent Nelson from Abra Kadabra and Klarion the Witch Boy. Frustrated with the way Kid Flash became careless in his pursuit of Miss Martian, she outed him as a non-believer of magic. Later, in a moment of friendship, she asked him how he was handling the team's latest adventure, and immediately became frustrated again when Wally explained away the magic he had just witnessed. Unbeknownst to her, Nelson suggested that Wally pursue Artemis; advice he promptly disregarded.
On his own birthday, Wally was tasked to deliver a heart to a child in need during a huge snow storm. He was to travel across the country in order to make the delivery while his teammates joined the League in a battle on the oil rigs. Feeling relegated to a small task, Wally was unprepared for the intervention of Vandal Savage during his journey. In the midst of his battle with Savage, Wally realized he was wasting time and proceeded back on his journey. Unfortunately, once he arrived at the hospital the staff informed him the girl had died, as he was a few minutes to late. Feeling extremely guilty for getting involved in a fight, Wally goes outside to cool off. He learned this was a ruse by Vandal Savage, and after a battle with Count Vertigo, Wally got the heart to the girl, who was revealed to be Queen Perdita of Vlatava.
As rumors of a mole was on the team spread Wally defended Artemis' position on the team from Red Arrow who suspected her. He was disappointed in her when it was revealed she lied to the team so she could take out Cheshire solo, because she was insecure about Red Arrow joining the team. Later when Artemis revealed she had not been lying, but keeping it secret that her parents, and sister were all wanted, or retired criminals, Wally put his arm around her to make sure she knew she was not alone.
Later in December following the climatic battle with the League, Wally and Artemis kissed after the stroke of midnight on New Years.