The school opened in September 1949 as Little Flower Catholic High School, after its patron saint, Therese of Lisieux. The first year had only a freshman class in a very small building on the grounds of St. Stanislaus Church in Lansdale. That building is still functioning on the property of St. Stanislaus, and today is called Little Flower Hall. Each succeeding year, another class/year was added and in 1953, commencement exercises were held for the first graduating class of 33 students. Probably the main, if not the only, driving force to bring about the establishment of the school was Monsignor Joseph Schade, who was the Pastor of St. Stanislaus at that time. He was aided in his efforts by the willingness of the Sisters of St. Francis of Assisi of Philadelphia who initially staffed the school, with Sister Theresa Clare being the first principal. In September 1960, the present facility opened at 7th Street and Lansdale Avenue on a property that consisted of approximately of land, and the first class graduated from there in 1961. Although the sports teams had long been referred to as Lansdale Catholic, it was with the opening of the new facility that the name of the school was "officially" changed to Lansdale Catholic High School. The school continued as a "parish" high school until the mid-1980s when control of the school was taken over by the Archdiocese. In 1988, there was the dedication of a major addition to the school. It was made possible primarily through the support of the . In more recent years, other improvements were added including another on-site parking facility, baseball field, window replacements, air-conditioning in the gymnasium, reconditioning of the football and lacrosse fields. Over the Summer of 2012, the gymnasium was completely refurbished with new floors and bleachers. On January 28, 2008, the Roman Catholic Archdiocese of Philadelphia announced that the school would move following the 2012 graduation pending funding. A new school, Lansdale Catholic Regional High School, in Hilltown Township, Bucks County, was to be built to replace the school in Lansdale. The name of the new school was voted by the students, parents and alumni. That project was cancelled because of financial reasons.
In 1998, the Lansdale Catholic football team won an ESPNESPY Awards for "Outrageous Play of the Year", with a "Cal-Stanford" play in a game against Upper Perkiomen.
In 2005 and 2006, the Lansdale Catholic girls' ice hockey team won the championship title. They won second place in 2003, 2004 and 2007. They have reached the championship round since they were deemed a team.
Peggy March, Class of 1966 - youngest female artist to have a number one single in the United States; she released "I Will Follow Him" in 1963, at the age of 15.
Timothy C. Senior, Class of 1977 - currently Roman Catholic auxiliary bishop of Philadelphia, wrote LCHS alma mater
Joe Judge, Class of 2000 - current head coach of the New York Giants
