The 21-year-old from the North Shore Golf Club, who has been playing on a golf scholarship at Mercer University in the States, delivered a birdie on the third hole of sudden death to secure the title.
Beale carded a one-under par 68 at the Elmhurst Golf and Country Club in Winnipeg to finish in a three-way tie at the top of the leaderboard with Canadian Taylor Pendrith (66) and American Jonathan Garrick (68) at six-under par 276.
The trio all made pars on the first two playoff holes, but it was Beale who made a lengthy birdie on the third hole to capture the title.
The former Kristin College student, who was in contention for the Eisenhower team this year, delivered an ultra-consistent week when he carded rounds of 69, 70, 68 and 69 in the world class field.
It secured Beale the biggest win of his amateur golf career as he followed in the footsteps of legendary amateur Stuart Jones, who is a member of the NZ Golf Hall of Fame, and Gareth Paddison who won the Canadian Amateur title in 1967 and 2001 respectively.
Beale continues New Zealand's incredible record of success in Canada adding his name to the list of winners that includes Jones, Paddison, the New Zealand team who won the Eisenhower Trophy in 1992 and Lydia Ko who won the Canadian Open on the LPGA Tour back to back.
With this victory, Beale, the No. 101 in the World Amateur Golf Ranking, has earned an invitation into next week's U.S. Amateur Championship at Atlanta Athletic Club in Johns Creek in Georgia and an exemption into the PGA Tour's Canadian Open in 2015.
For most of the day, it didn't look like a playoff was going to be needed.
American Rico Hoey took command of the leaderboard by getting to seven-under par for the tournament but he faltered down the stretch with a bogey-double bogey finish.
Beale took full advantage to become the third Kiwi golfer to win the event and the first in 13 years.
South Australian Antonio Murdaca did best of the Australians when he finished 11th.