The Australian maintained his perfect record of seven wins from seven finals in major tournaments by defeating Englishman Shaun Murphy 10-6 at Alexandra Palace in north London.
The week-long Masters is considered one of the toughest tournaments to win because it only involves the world’s top 16 players.
Robertson, who collected £150,000 for his efforts, is the first Australian and only the fourth player from outside Britain to win the Masters.
Having won the 2010 world championship, the 29-year-old only needs to take out the UK Championship to become the first non-British player to complete the Triple Crown.
“It means a lot after the world championship. This is the tournament that I really wanted to win,” Robertson said. “In order to win this tournament, you have to beat all the best players in the world and my path to the final has not been easy.
“I am absolutely over the moon. Everyone in Australia will be watching and just a thank you to all the support I received.”
World No.4 Robertson celebrated the title with his Norwegian partner Millie and briefly let his toddler son Alexander loose on the table.
The Victorian’s tale of persistence is worth retelling. He has only cut it professionally at his third attempt, having arrived in Cambridge with £500 of borrowed money and needing to be lent a waistcoat for competition.
Robertson emerged out of a tight first session on Sunday night with a 5-3 lead before charging out to a 9-4 advantage. However with victory in sight, Murphy relaxed and collected the next two frames before Robertson held his nerve to take out the win.
Chants of “Aussie Aussie Aussie, Oi Oi Oi” kicked off once he had seized a match-winning lead in the final frame of the best-of-19 final. Robertson’s one-year-old son Alexander joined in the applause by clapping his father’s victory during the presentation.
The Australian had a tough path to the final, defeating two-time world champion Mark Williams, 2011 UK Championship finalist Mark Allen and rising star Judd Trump.
The vanquished Murphy led the plaudits for Robertson.
“The lad is class,” he said. “He is a credit to his family and his country and our game. “We are lucky to have someone like Neil involved in our game. He is a true pro and he played better than me on the day.”