|Date of birth||18 June 1948|
|Place of birth||Lucerne, Switzerland|
|Height||1.70 m (5 ft 7 in)|
|* Senior club appearances and goals counted for the domestic league only.
Hasler started his career at FC Zürich in 1969 and left two years later to join FC Basel, where he won two league titles consecutively in 1972 and 1973, and the Swiss Cup in 1975. He then moved to Neuchâtel Xamax in 1976 where he played for three years before returning to St. Jakob Stadium, where he helped Basel win another title in 1980.
Hasler earned 25 caps for the Swiss national team, the first of which coming on 21 October 1972 in a 0-0 draw with Italy in Bern. His last game in a Switzerland shirt was a 2-1 loss to Spain on 21 September 1977, also in Bern.
- Swiss Cup: 1970