In 1999, she joined Kanyomozi, her former schoolmate at Namasagali College, to form the R&B all-girl group called I-Jay.[5] According to Bryan Morel Publications, In 2000, they released their first 7 track album titled "WAIT" which included songs "Wait RMX (Ft Steve Jean)", "Not Good Enough", "Mwana", "Wait", "Emirimu", "Vivi LA Vi" and "Two To Make It True...", which received moderate air play on radio stations in Uganda.
However, Namubiru did not achieve widespread success until 2006, when she released her album Nkuweeki?.[6] Since 2006, Namubiru released the songs "Y'ono", "Lwaki", "Bonna Obasinga", "Begombeko", "Birowoozo", for which she has received various awards in the Ugandan music industry.[7] In 2011, Namubiru won in four categories of the 2011 Pearl of Africa Music Awards (PAM). She won in the categories of Artist of the Year, Female Artist of the Year, Album of the Year and Best RnB Single of the Year.[8][9][10]