McMaster started playing for the Palm Beach Sharks and Surfers Paradise before moving to the Queensland Lions. In 2005, the A-League was formed and Queensland Roar were given a license to be a part of the new 8-team competition. McMaster trained with the club under then coach Miron Bleiberg and played in the Brisbane state league for Brisbane City and Mt Gravatt. In July 2007, McMaster signed as a replacement for injured goalkeeper Matt Ham under new coach Frank Farina. He was understudy to Liam Reddy. Following an injury to keeper Liam Reddy, McMaster made his A-League debut on 5 January 2008 against Melbourne Victory and was named man of the match. McMaster played another man of the match performance in that season in a finals game against Sydney FC. He was replaced by Reddy for the following match, however he re-signed for two more seasons. McMaster received limited game time under coach Farina before the sacking of Farina in October 2009. Ange Postecoglou was appointed the new coach and Reddy succumbed to another injury. McMaster played 12 games under Postecoglou before he was released by Brisbane Roar in March 2010 and joined Victorian Premier League club Oakleigh Cannons. In August 2010, McMaster was signed by Wellington Phoenix on an injury replacement deal for injured goalkeeper Reece Crowther. McMaster signed for Heidelberg United to play in the 2011 season and won Victorian Premier League keeper of the year. Towards the end of the 2011 Victorian Premier League season, McMaster was trialing with Melbourne Heart. He fractured his tibia in round 19 of the Victorian Premier League against Northcote City and was sidelined for 10 months. In March 2012, McMaster signed with sport marketing company Upper90 Sports for 2 years. He also made a successful recovery from his broken leg for Moreland Zebras against South Melbourne in the Victorian Premier League. He left Moreland Zebras at the end of round 19 to join Bentleigh Greens for the remainder of the season. On 30 November 2012, McMaster joined the Wellington Phoenix for a second injury replacement stint this time as cover for Glen Moss. In 2014, McMaster made a return to Heidelberg United in the inaugural NPL season in Victoria. He has been making consistent appearances under coach George Katsakis. He has made a number of occasions on SEN radio on the football segment with Mark Fine. In February 2016, it was confirmed that McMaster had left the Bergers to join the newly promoted FC Bulleen Lions. McMaster signed for Northcote City in 2017 playing most of the season and helping team gain promotion to the National Premier league. McMaster retired but returned with Altona City in 2019 playing 8 matches before returning back to his old club Northcote City. In 2020 McMaster signed for Altona Magic making 2 appearances. Because Covid19 occurred, the competition came to a complete halt and McMaster decided to hang up the gloves.
Music Career
McMaster began music producing in 2017 under the DJ name 'Mastered' and has steadily gained a following on Soundcloud and Spotify. He has a number of tracks signed with overseas labels. Yeiskomp records relseased two tracks 'Heartbeat' and 'Trella'. He also has a third track signed with Los Angeles Label Fuzion Four records.
On 29 July 2015, McMaster attracted negative attention and criticism which were directed at Australian AFL player Adam Goodes. In McMaster's tweets, he criticised Goodes' view of Australia Day as "Invasion Day", attacked Goodes for "not celebrating Australia Day", and called for the Aboriginal Australian to be "deported" from Australia, Goodes' ancestral land. McMaster soon deleted the tweets, in the face of significant controversy and criticism, followed by a message stating "f anyone is offended...y apologies". McMaster was subsequently omitted from the FFA game on the evening of the 29 July. The following statement was made by Football Federation Australia, as reported by ABC news: "Football Federation Australia applauds Heidelberg United Football Club for standing goalkeeper Griffin McMaster down from tonight's FFA Cup match following a series of offensive tweets this afternoon".
