The corps became the Hyde Park Crusaders sometime after 1955 when they lost church sponsorship, possibly because the church limited membership to church parishioners; the name became the Boston Crusaders sometime after 1958. Then and throughout their history, the group has cherished a reputation as the corps that would not die.

In 1957, the corps' second season after leaving the Church, they wanted to get new uniforms, having marched in 1956 in their old Most Prescious Blood unis. The new uniform was derived from St. Joseph's Cadets of Newark but the colors were changed from orange, blue and yellow to the classic Boston red, black and white.

Their resiliency was supported by the informal patronage of John F. and Ted Kennedy, both of whom were made honorary corps members. It was JFK who helped the corps acquire West Point uniforms after their own were held by their Hyde Park sponsor. The corps in turn helped to celebrate their supporter's achievement by becoming one of the first drum corps to march in a presidential inaugural parade, for President Kennedy in 1961.

BAC (Boston Area Crusaders), as they are known, was one of the powers in the East in the sixties. They won the first CYO National Championship in 1964, then again in 1966 and 1967. They also took the World Open in 1966 and '67. They took part in VFW Finals in 1969 and 1970. The corps might have won it all in 1967 except that the American Legion decided to void the inspection scores, which cost the Crusaders the national championship. As it was, BAC won 29 contests that year.

A particularly strong soprano soloist in the late 1960s was Jim Centorino.

BAC also was known to mean "Bad-ass Crusaders." During some eras in some parts of the country, tough competitive corps on the field were equally tough off the field, to the point of physically intimidating other corps. These corps might almost have been characterized as musical gangs, as adept with fists as with bugles. The Crusaders were particularly effective competitors off the field. One memorable incident involved corps members chasing off a gang of local toughs just before marching DCI Prelims in the Orange Bowl in 1983. Even 21st century corps members know that BAC does not necessarily stand just for "Boston Area Crusaders."

Although a charter member of DCI, the corps opted not to take part in the first DCI Championships in 1972, choosing the CYO Nationals instead. They had lost much of their equipment in a fire in their corps hall that summer, forcing the corps off the road and out of competition. At one time BAC was down to 19 members. Taking 39th place in DCI prelims in 1973, they steadily climbed through the ranks during the 1970s. DCI used to offer parade competition, and the Crusaders won that contest in 1981.

A historic visit to the United Kingdom in 1982 was another disastrous turning point in the corps' history. During that trip, money was embezzled from their funds, and the corps was stuck in the UK, dead broke. Although somehow making their way home, their trail of debts left the corps bankrupt and all of their assets impounded. During that winter, in an effort to resurrect the corps, members actually stole the organization's truck, uniforms, and equipment, and appeared the following year under the shortened name "Boston." Debts were finally settled after many months, and "Boston" once again took back their rightful name. Interestingly, Boston's emergence from bankruptcy in 1986 coincides with the demise of cross-town rival 27th Lancers, due to financial failure.

Even such a luminary as Burt Lancaster was inspired by the example of this corps that refused to die. In a 1991 Variety interview, he said, "Before he lost it, Peckinpah made me go see this drum and bugle corps from Boston, the Boston Crusaders. Sam thought I would only really understand the power beneath despair by watching these guys. Yeah, he was right. In '73 and '83, the corps went out with just handfuls of guys on the horns and, damnit, those man-gods could melt the gates of hell. Every single film I made after 'Valdez is Coming' is an allegory on the Boston Crusaders."

Management structure, according to Jim Cronin, was not well suited to greater corps development, regardless of talent on the field. A reputation throughout DCI as toughs and troublemakers did not help the Crusaders' progress either, and BAC settled into the middle rank of DCI through the late 1980s and early 1990s.

Their repertoires over the years were an eclectic mix, from Beethoven’s Ninth to “Mexicali Nose.” BAC actually first used electrification in 1985 when they fielded a synthesizer. They took a penalty for it.

The corps claims other pioneering innovations as well, such as the first double toms in 1967, the first marching tymps in 1968, and the first to pull slides on the bugles to achieve a chromatic scale.

In 1999, the Boston Crusaders under director Jim Cronin (1996-2000) became the last major active corps to finally break into the DCI top twelve, at ninth place, with a program of symphonic dances. A new philosophy stressing “professionalism, accountability, and responsibility” instilled in the members of the “new” Boston Crusaders that “how they act off the field is as important as how they perform on the field. Everything is about a positive attitude, the way they treat each other, peer respect.“ No more Bad Ass Crusaders.

Their themed 2000 program entitled 'Red' give the Crusaders their highest ever DCI finish, at fifth, and prompted one observer to conclude that he had never seen a more coherently organized and satisfying drum corps show.

Jim Cronin makes the point that a corps presence on the Internet has been helpful in reaching potential members in recent years. Whereas most of the Crusaders used to come from the Boston area, the web has generated interest and membership from elsewhere, overseas as well as around the United States. Only 20 members of the 1997 group hailed from Boston, solidifying the Crusaders as actually more of a New England corps, the last Division I corps in the area. The 2000 version of the Crusaders in particular benefited from an influx of members from Florida.

Howard Weinstein became corps director in early 2001, and led the corps to a ninth place finals finish with a show entitled 'Harmonium.' The Crusaders moved up, even during finals week, in 2002, from eighth to a fifth place finish, with their show 'You are my Star.' Their 2003 finish was sixth.

The advent of legal amplication in 2004 allowed the Crusaders to electronically project voices as well as instruments when they added a brief exclamatory narration to their show 'The Composition of Color.' The corps took ninth place in Finals, their sixth straight top ten finish.