Prosecutors say Diego Suero and Frederick Then ordered the hit on the 15-year-old, who was dragged out of a bodega in Tremont and stabbed to death in 2018.
The two men face 25 years to life in prison when they are sentenced in September.
Five other young men have also been convicted in the killing.
Junior's murder launched an international social-media movement under the hashtag #justiceforjunior that sought justice for the teen.
Leandra Feliz, the mother of the Bronx teenager, became the face of grief for Junior. She has been advocating for a bill to have panic buttons installed in all bodegas.
"My son has already passed," she said last year of what she hoped would be called Junior's Law. "They killed my son. We have to protect our future kids and our community."
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