He is mentioned in Acts 15:22, where he and Silas are described as a "leading men among the brothers" (NIV). Judas and Silas were delegated the task of accompanying Paul and Barnabas to Antioch and delivering the Council's letter resolving the controversy surrounding gentile circumcision.
Acts 15:32 further describes Judas and Silas as prophets, and says that they "said much to encourage and strengthen the believers." After a stay in Antioch, Judas returned to Jerusalem whereas Silas remained in Antioch.
† Recognized as a prophet. ‡Status as a prophet is not universally recognized