In February, Smith headed to USA where he made the quarter final of the Dallas Challenger. He then played and qualified for the Delray Beach main draw. This was fourth ATP World Tour event for which he has qualified. He drew No.1 seed Kevin Anderson and lost in round 1. Smith lost in round 1 of qualifying for Indian Wells before returning to the Challenger tour, where he won the Drummondville Challenger over crowd favourite, Frank Dancevic. This was his second career Challenger title and first since 2012. This win gave Smith a near career high of 163. In June, Smith secured his first Grand Slam main draw entry via qualifying for the first time in his career at Wimbledon. He lost in round 1 to Kenny de Schepper in 5 sets, despite leading 2 sets to 0. In July, Smith entered the Newport Championships and defeated compatriot and third seed Bernard Tomic in round one, his first win on the ATP World Tour  on the way to the semi final where he lost to eventual champion Rajeev Ram. At the US Open, Smith qualified before losing to Mikhail Youzhny in round 1. Smith ended 2015 with a ranking of 129. Smith began 2016 with a wild card into the 2016 Brisbane International. He lost in round 1. Smith made the second round of qualifying at the Australian Open. In February, Smith qualified for Delray and defeated world number 26 and number 3 seed Ivo Karlović in round 1. He lost to Juan Martín del Potro in round 2. He lost in the qualifying rounds of Mexican Open, Indian Wells and Miami Masters. In April and May, Smith returned to the Challenger Circuit across Asia and Europe with limited success. In June, Smith lost in round 1 of Wimbledon qualifying. In July, Smith defeated compatriot Jordan Thompson in round 1 of Hall of Fame Tennis Championship, but lost to Marco Chiudinelli in round 2. Smith lost in round 1 of US Open qualifying before returning to the Challenger circuit in USA and Australia in September, October and November. Smith ended 2016 with a singles ranking of 226. Smith began 2017 narrowly missing out on qualifying for 2017 Brisbane International and 2017 Australian Open, before playing a number of challengers in North America. His best result being a semi-final result at Drummondville in March. In April, Smith travelled to Europe and lost in the first round of qualifying for the 2017 French Open and Surbiton Challenger before qualifying for and making the quarter finals of the Nottingham Challenger in June. At Wimbledon, Smith lost in the last round of qualifying, 10–12 in the fifth set.