SM Entertainment revealed individual photograph teasers of each member for the new album starting with Minho on July 8, 2010 and ending with Key on July 12, 2010. A teaser for the music video of the lead single was released on July 14, 2010 at the official channel of SM Entertainment on YouTube. The group was originally set to have their comeback stage on KBS Music Bank, July 16, to begin their promotions for the new album, however, due to Minho injuring his ankle during filming of Dream Team Season 2 on July 8, the comeback was postponed to July 23, 2010.
The second full length studio album, entitled Lucifer, was released on July 19, 2010 in South Korea. The music video promoting the lead single, also named Lucifer, was released on the same day. Within hours of the release, the album topped various physical and digital sales charts in South Korea.The songs on the album "were more carefully selected than ever", and the album is said to "[give] listeners a great chance to experience the diverse musical characters and more mature vocal skills of the members." The group made their comeback on July 23, 2010 at KBS Music Bank. Choreography of "Lucifer" was released on the same YouTube channel on August 3, 2010. The studio album was re-released as a repackaged version, entitled Hello, on October 1, 2010. The music video of the promotional single, also named "Hello", was released on October 4, 2010. The re-released version included three new tracks.
Amidst their promotional activities for the second studio album, the group also participated in the SMTown Live '10 World Tour alongside their label-mates. On August 21, 2010, they performed in a concert at Seoul Olympic Stadium in Seoul.On September 4, 2010, they also performed at a concert at Staples Center in Los Angeles. Later, on September 11, 2010, Shinee also participated in a concert at Hongkou Stadium in Shanghai.
On December 26, 2010, Shinee started their first concert tour, Shinee World by holding their concert at Yoyogi National Gymnasium in Tokyo. The event was attended by a total audience of approximately 24,000 attendees. The group also announced that they will be releasing their first Japanese language studio release in 2011 under EMI Music Japan, a record label known for the success of their famous Japanese-American singer-songwriter Hikaru Utada.
