Johnston's first manager, Myles Shear, discovered him on SoundCloud and flew him to Miami. 　　Johnston began a podcast mix series called Tropical House, which featured guest mixes by Felix Jaehn, Bakermat, Robin Schulz, and others. He became well-known across EDM websites for his original tracks such as "Symphony" and "The Final Speech" as well as his remixes of popular artists such as Of Monsters & Men and OneRepublic and house producers like Adrian Lux. 　　His busy touring schedule brought him to clubs around the globe, causing Johnston to refer to himself as "homeless" but he has spent a considerable amount of time in the United States, particularly in Florida. After devoting much of 2014 to remixes (including his take on Gabriel Rios' "Gold") and live gigs, he released a new single, "Rivers". In August 2015, Johnston went on the We Are Your Friends movie tour along with several other artists such as Hook n Sling, MAKJ, SNBRN, Anna Lunoe and Michael Woods.Johnston announced the Tropical Express Tour in which he toured with Bag Raiders, Bixel Boys, Felix Jaehn and several others. 　　On 30 October 2015, Johnston released his debut single "Rivers" featuring Norwegian singers Nico & Vinz.The single peaked fourth on the Belgian chart, fifty-first on the Dutch chart and sixteenth on the Norwegian chart. On 26 November 2015, an official music video was uploaded to Thomas Jack's YouTube channel. 　　When asked about his plans on launching a tropical house record label, Johnston said "Maybe, but I'm trying to figure out what music I want to make still. There's a lot of different stuff I want to make. I just want to get there first. I discovered so much amazing music at Burning Man that really inspired me to do some different things. It's hard to change straight away. I got some different ideas for what I want to do. But they're a bit too weird to change so I'm just gonna keep cruising. I've got an album to finish at the moment which is pretty cool". 　　Johnston had planned to release his debut studio album in 2016.[4] He said "I'm just starting to get into it now, so I'm not sure. I have some new singles, but we're just trying to figure out the correct release dates and everything. I've had such a hectic tour schedule over the summer, so it really slowed down my production. But I have a bit of time off now, so I can focus. I'm looking forward to it". 　　On 8 July 2016, he released his second single "Rise Up" with English singer Jasmine Thompson. The single peaked fourteenth in Belgium. An official music video was uploaded to Jasmine Thompson's YouTube channel.