On 18 November 2008, it was announced that Zelmerlöw would again compete in Melodifestivalen, this time with the song "Hope & Glory". The 2009 contest featured many former entrants, including Sarah Dawn Finer, Sofia, BWO and Amy Diamond. He took part in the second semi-final on 14 February 2009, and again progressed to the final on 14 March at Globen. "Hope & Glory" ultimately placed fourth, despite receiving the most votes from the jury.
In 2008, Zelmerlöw went back to the studio to work on his second solo album, MZW, which was released in late March 2009. It was certified gold by the IFPI and reached number one on the Swedish album charts. The album was also released in Poland. In 2009 he played a summer tour of Sweden performing songs from both albums.
Between 2008 and 2011, he was in a relationship with the Swedish singer and model Marie Serneholt, a former member of the Swedish pop band A-Teens. In 2016, Zelmerlöw began dating English actress Ciara Janson and they later announced their engagement. In December 2017, Zelmerlöw announced that they were expecting a child together. A few weeks later, he confirmed that the child would be a baby boy. The couple live in London. On 25 May 2018 he announced via social media that Ciara had given birth to their son, Albert. The couple married on 5 September 2019.