[1] As a 15-year-old Bruen entered the 1935 Boys Amateur Championship at Royal Aberdeen Golf Club but lost his first match.

Bruen continued to dominate in the afternoon and eventually won 11&9, to become the first Irish winner of the championship.

[6] In May 1937 Bruen travelled to Royal St George's Golf Club for his first Amateur Championship.

Prior to main event he was runner-up in the St George's Vase and, the following day, in the Prince of Wales Cup.

In the Amateur Championship, three day later, he met American Dick Chapman in his first match and lost 2&1.

[7] In June, Bruen won the Irish Amateur Close Championship at Ballybunion Golf Club, beating five-times champion, John Burke, in the final.

[8] In July, he played in the Irish Open and finished as leading amateur, tied for 6th place.

On the second day Bruen was again out first against Charlie Yates, who had won the Amateur Championship the previous week.

[11] Later in the month, Bruen successfully defended the Irish Amateur Close Championship at Castle Golf Club, beating Redmond Simcox 3&2 in the final.

In the first round at Royal St George's Golf Club he scored 70 to be joint leader but took 80 on the second day.

[13] Later in the month he played in the Irish Open and again finished as leading amateur, tied for 10th place.

[16] In the Irish Amateur Close Championship at Rosses Point Golf Club the following month, Bruen again lost at the quarter-final stage, beaten by eventual winner Gerry Owens.

[20] With the start of World War II important amateur events in the United Kingdom came to a stop.

Bruen won the first Amateur Championship after the war at Birkdale Golf Club, beating the 1937 champion Robert Sweeny Jr. 4&3 in the 36-hole final.

Despite withdrawing from the Amateur Championship, he was chosen for the 1949 Walker Cup team, to be held at Winged Foot Golf Club in Mamaroneck, New York in mid-August.

[1] Bruen died from a heart attack in Bon Secours Hospital, Cork on 3 May 1972, five days short of his 52nd birthday.