Smith was born in Cape Town, Western Cape, South Africa. He started hockey at the age of five years, and his parents played hockey for a number of years in South Africa and England. It was at Smith's Primary School, Pinelands North, where he was introduced to hockey, among other sports. His coach at Pinelands, Murray Anderson, inspired Smith to focus on hockey. When Smith started at Pinelands High School he had already achieved success, having represented his Province at U13 level. He went on to represent South Africa U16 and U18 teams and became captain of each. He attributes a large amount of his achievement to one factor: "I was extremely lucky to have such dedicated coaches at both my Primary and High School. Michael McConnachie who spearheaded the hockey at the High School was my biggest mentor, and made me truly believe in myself." In March 2004 aged 18, Smith achieved his lifelong dream of representing his country at a senior level. "It was an incredible feeling walking onto the field to play my first match for South Africa, and it remains a special moment every time I wear the green and gold." In 2005 Austin represented South Africa at the U21 World Cup in Rotterdam, the Netherlands. Smith moved to the United Kingdom in 2005 to join Reading Hockey Club. He spent four seasons at Reading, winning the Premier League twice and making the final eight of the Euro Hockey League on consecutive occasions. 2008 was a defining year in Smith's hockey career as he achieved another childhood dream by attending the Olympic Games. Despite South Africa's final placing of 12th in Beijing, he was the team's top goal scorer with four goals. To finish off the year he was named South African Men's Hockey Player of the Year as well as Reading Hockey Club's Player of the Year. In 2009 Smith decided to leave the UK to join HC 's-Hertogenbosch in The Netherlands. Earlier on in the year he was named the captain of the South African squad, and leading them to victory in the African Championship to qualify for the World Cup in 2010. Smith was also named in the World All-Star Team for his performances in 2009. In 2010 Smith captained the South African squad at the World Cup and the Commonwealth Games where they finished in 10th and 5th respectively. Later on in the year, he was named South African Men's Hockey Player of the Year for a second time.
