1920s
- June 1920 - The sod is turned for St. Peter's College
- June 29, 1921 - The cornerstone is laid for the College. A colony-wide celebration is held, attracting over 3,000 people. Many of the surrounding towns declare a holiday to attend the pontifical High Mass.
- 1921 - The monastic community moves into the new College building in November and classes for the 36 registered students begin immediately.
- 1926 - The College becomes affiliated with the University of Saskatchewa
1930s
- 1937-1938 - St. Peter's College hockey team wins the Platzer Cup, emblematic of hockey supremacy in the Humboldt district.
- 1938-1939 - St. Peter's College "Blue Jays" win a second successive Platzer Cup
1940s
- 1948 - Abbot Michael Ott dies. The College building, Michael Hall, was named for him.
- 1948-1949 - St. Peter's College hockey team wins the Platzer Cup.
1950s
- One of the last projects of Fr. Xavier's tenure as rector of the College (1935-1960) was the introduction of evening university classes.
- Start of construction of St. Scholastica Convent for the Sisters of St. Elizabeth who provided domestic service for the monks and students
- 1959-1960 - Construction of a gymnasium to replace the original one and construction of a residence wing-Severin Hall.
1960s
- 1962-1963 - A new monastery is built, freeing up more space for classrooms and recreational space for students
- 1965 - An indoor ice-skating rink is constructed
- 1966 - University classes are opened to women
1970s
- Saskatchewan Writers Guild begin to hold summer and winter sessions at St. Peter's
- 1972 - The College high school is closed, but university classes continue.
- 1978 - The Abbey guest wing is established in the old high school residence
1980s
- 1980 - The 1500th anniversary of the birth of St. Benedict
- 1989 - The first lay principal, Tony Saretsky, is appointed
1990s
- The St. Peter's College Faculty Association is formed
- 1993 - The position of president is created, with Wendy Schissel and Barry Popowich being the first co-presidents of the College
- 1997 - Centre for Rural Studies and Enrichment is established under the direction of Diane Martz