Though St. Lawrence today is nonsectarian, it was founded in 1856 by leaders of the Universalist Church, who were seeking to establish a seminary west of New England and were enthusiastically courted by the citizens of Canton.

The church almost did not place the school in Canton, however, as they felt students might be exposed to too much "excitement" within the village limits in 1856.

The denomination, which has since merged with the Unitarian faith, was part of the liberal wing of Protestantism, championing such ideas as critical thinking and sex equality — attributes that surfaced in the new Theological School of St. Lawrence University, which was progressive in its teaching philosophy and coeducational from the beginning.

The university as it exists today was created as a "Preparatory Department" to provide a foundation for theological study.

Early in the 20th century, the university's graduate program in education came into being; it has since served hundreds of North Country school teachers and administrators.

Following a difficult period during the Great Depression and World War II that included the decision to shut down the Brooklyn Law School,[5] the student population increased quickly, and with it, the physical plant.

St. Lawrence has 3+2 engineering programs run jointly with five other colleges, and a 4+1 MBA at Clarkson University.

Its most popular undergraduate majors, based on 2021 graduates, were:[15] St. Lawrence offers international programs in Australia, Austria, Canada, China, Costa Rica, Czech Republic, Denmark, England, France, Germany, India, Italy, Japan, Kenya, Nepal, New Zealand, Spain, Sweden, Thailand, and Trinidad and Tobago.

Each semester the special collections staff offer instruction to classes from a variety of academic departments and programs, including fine arts, French, English, history, environmental studies, economics and the outdoor studies program.

Other special collections include manuscripts devoted to Frederic Remington, the Adirondacks, the St. Lawrence Seaway and other aspects of northern New York history.

Instrumentalists may choose between participation in the String Orchestra, Concert Band, Improv Lab, Early Music Ensemble and Special Productions.

Three informal student-directed collegiate a cappella groups, The Saints, The Sinners, and The Upbeats are active both on and off campus.

St. Lawrence University is also home to the Java Barn, an on-campus music venue run by a dedicated group of SLU students.

The Java Barn hosts live bands every weekend; shows are open to all SLU students and admission is free.

In addition, the flexible 85- to 100-seat Edison Miles Theater (better known as the Black Box) is used for experimental and student productions.

Paintings and sculptures by Frank Stella, George Segal, Louise Nevelson, Isamu Noguchi, Milton Avery and Frederic Remington are among the collection's highlights.

St. Lawrence is home to the second oldest collegiate outing club in the nation (next to only Dartmouth College).

The club frequently sponsors trips for skiing, hiking, rafting and other outdoor activities.

Established in 1993 as a student-run coffeehouse, the Java Barn is a well-known venue among touring bands on the East Coast.

Java now occupies a former storage garage, with bright student-created murals spattering the walls.

Commons College residents focus on charity fund-raising and building a living-learning experience through a house-shared course each semester.

Students in the Greenhouse live in an environmentally responsible manner, and provide weekly, healthy, locally sourced dinners.

There is also a technology-centric theme house, The Hub, which provides gaming and technology events to the campus.

The current state of Greek participation levels are substantially lower than in past years, due in part to liability issues and national chapter concerns over various alcohol and code violations.

Students live together and study in a team-taught FYP, developing the writing, speaking, and research skills needed for college.

The Saints hockey team compete at the NCAA Division-I Level in the ECAC league for both men and women.

They play their home games and have additional training facilities in Appleton Arena which has a capacity of approximately 3,000 and was constructed in 1951.

In 2000, the Saints played in the longest NCAA tournament game on record; a 3–2, quadruple overtime victory over Boston University.

The win advanced the Saints to the Frozen Four, where the team eventually lost to Boston College in the national semifinals.

They were runners-up for the NCAA Championship in 2001 and made appearances at the Frozen Four in 2004, 2005, 2006 and 2007, the last of which they hosted in Lake Placid, New York.