Brier won the Swiss and German Amateur Opens in the mid-1990s, and turned professional in 1995 at a relatively late age. Nine top ten finishes, including five top threes, on the 1999 Challenge Tour earned him third place on the season ending money list and playing privileges on the European Tour for 2000. He retained his tour card through his final position on the order of merit every year, except for 2002 and 2010 when he regained it through final qualifying school.
Since joining the European Tour, Brier has continued to play in his home event, the Austrian Open, winning it on two occasions during a period when it was a Challenge Tour event. In 2006 the tournament was promoted back onto the main European Tour schedule, now under the sponsored title BA-CA Golf Open. In its first year back, Brier once again took the title, in the process becoming the first Austrian golfer to win a European Tour event. This win helped him to his then best year-end finish on the Order of Merit of 49th.
Brier’s second European Tour win came in 2007 at the Volvo China Open and he improved his position on the year end Order of Merit to 32nd. He has also featured in the top 100 of the Official World Golf Rankings.