The Chicago Lions Rugby Club (formerly known as the Chicago Rugby Football Club) was founded by William Walker in 1964 with the help of the Honorable Philip G.D. Adams and the Chicago Rugby Clubs first coach, Peter Wood. The Chicago Rugby Club played on the Northside of Chicago against multiple club and collegiate teams such as the University of Illinois and Wisconsin and Palmer school of chiropractic.

In 1965 Dick Smith, a securities broker, was elected president of the Lions and started working towards a better future for the club immediately. The club was renamed the Chicago Lions Rugby Club, and a tradition of hard work and perseverance was born. By 1966, the Lions presented a formidable force, going undefeated in nineteen straight matches, and in 1967 when, they entered and won the first Mid-American Cup hosted by the Tri-State Union. An Intimidating black and white kit influenced by the All Blacks, paired with a determination to dominate, set the Lions apart from the competition quickly as the Lions walked away with the first and second Mid-American Cup (1968).

The Lions went back in 1970 to claim another title after returning from a successful English tour the season before. In 1972 the Lions claimed their fourth title with Mike King leading the team on the pitch and Dick Smith leading from the front. The 1973 team competed with the Northhampton Saints and Cirencester RFC on their home pitch. Led by Lawrence Kinet, ventured on the third European tour to Scotland and England.

First-year President Bob Avery, along with the help of Captain Lawrence Kinet, overtook the Midwest competition again that year as the Lions earned their fifth Mid-American Cup, and the next year, the Lions were back to stand again and hold their sixth Mid-American Cup, their third in a row (1972-1974). As the Club grew, the Lions continued to test themselves by playing as many foreign teams as they could, and the Thanksgiving season of 1974 saw a trip to Jamaica and then a match against Greystone RFC from Ireland. 1976 saw the Club’s first victory over a foreign side when the Chicago Lions handed Bingley RFC from England a defeat of 19-9.

The 1976 season was the same year the Club was able to lay hands on their seventh Mid-American Cup and ended the season on a high note in Hawaii. From 1976 to 1983, a huge part of the Lions' success came from their leader and President J. “Tyke” Nollman, whose administrative skills led the Lions to stay at the forefront of USA Rugby.

A fourth tour to England in 1977 saw the Lions facing off against English and Irish sides; during this time, the first USA XV team was making a similar trek across the Atlantic to face England’s national side. In 1978, the game of rugby had grown so much that it was clear that a national championship would take place soon. The Lions were confident that their history and resume, containing eight Midwest championships, put them in an excellent place to take a shot at the National title. At the end of the 78 season, the Lions traveled to the Cayman Islands.

President “Tyke” and Captain Gary Wilson, an English foreigner who had been a crucial part of the Lion's game plan and leadership, prepared the Club for their first-ever National Championship. The Club was unable to make an appearance in Nationals, unfortunately, as a narrow loss to Akron in the 1979 Mid-American Cup final left the Lions out of the National competition.

1980 was the year that truly tested the grit of the Chicago Lions. Coming off of successful seasons but disappointing losses in the Mid-West tournament left the Lions and “Tyke,” along with the administration, with two bold goals. One was to win a national championship, and the other was to send the very best of the Club on a tour of South Africa. In order to reach these goals, the Club had to prepare, and four international teams were invited to come to Chicago. The first to come was Monkstown Ireland RFC, followed by Streatham Croyden from England, then the University College of Dublin, Ireland, followed by the historic South African team the Mbabalas, which was the first all-black team to be allowed to tour in the USA from South Africa. The Club finished with a respectable record of an even win/loss to the competitors. These campaigns may have helped the Lions gain some experience but not enough to make it past the Mid-American final, losing to Michigan 9-8. After the disappointing loss, attention was turned to the summer tour schedule containing four tough regional sides along with an opening game where the Lions would face the Pretoria Harlequins in a Springbok vs. British and Irish Lions pre-match. These games would prove to be crucial for the development of the Lions ' play and coaching style for years to come.

1981 was a disappointing year for the Lions, losing in the Mid-American semi-finals to a strong Minneapolis team, which then went on to represent the Midwest at the National competition in Dayton. This was a crucial year for the Lions, pioneering USA Rugby by being one of the first clubs to buy property for the Club’s own use. For the 17 years before this, the Club had been practicing and playing at a multitude of different parks in the Lincoln Park area, and numerous pubs had been used as meeting points for the team and for parties. A committee had been formed in 1980 to purchase a building on the near north side of Chicago, which contained a tavern and four apartments, providing the Club with both income property and a clubhouse. Lions such as Ed Kane, Mike Cavanagh, Tim Grossnickle, Bruce Reinwald, Chuck Pfau, and many others were instrumental in the purchase and refurbishing of the new home for the Chicago Lions. The Fall of 1981 saw weekly parties on 1801 West School Street as well as success on the pitch. During the 1981 fall, South Africa and Ireland clubs both visited the Lions and participated in matches that both sides called a success.

The Midwest league system was instituted during the 81’ Fall, which changed how the sides were bracketed and picked to compete for the Midwest title. The 81 season was closed out with a social tournament in Barbados, giving the club members a relaxing way to experience different types of rugby. In the spring of 1982, Captain Gary Larson brought the team to Memphis to kick off the season. He then led them to the Lions Ninth Mid-American Cup and to represent the Midwest at the National level, where the Club took 4th, losing to four-time national champions Old Blue of Berkeley, California. During this year, the Lions' old boys and alumni decided to start a branch of Lions to join social tournaments and named the team The School Street Fat Cats. To qualify to be on a Fat Cats side, all players had to be over 200 lbs, with one payer on each Fat Cats side being allowed to be under 200 lbs. Another Fat Cats rule was that all players wore number 6 for the late Mark Swinney.

The spring of 1983 saw the Lions' captaincy shift to Paul McNaughton, a former Ireland national team member. McNaughton brought a wealth of knowledge to the Club and maintained the mindset that the National Championship, which was to be held in Chicago for the first time, was the goal for the season. A tough season against Midwest teams, as well as some outliers such as Life University and another club from Atlanta, brought the 83’ season to an end with the Lion's 10th Mid-American Cup. However, the Lions faced another defeat to Old Blue in the National championship tournament. Old Blue would move on to be that year’s National Champion. In 1984, the Club once again retained the Mid-American Cup under new Lions Head Coach Australian Geoff Schweger. Bringing their Midwest titles to eleven. The Lions moved on to the National Championship but lost to the Dallas Harlequins, placing the Club in 3rd in the nation for the second season in a row. A second tour to South Africa was planned and formalized for the 1985 season. 1985 saw a new president and captain as it passed to Rich Joseph, a tenured lion, to be president and Dan Halm to be the captain. This season was kicked off with a sweep of the St. Louis Bombers as well as the new team, the St. Louis Black Sheep. However, victory was short-lived as the Lions were outmatched during league play and were not eligible to compete for the Midwest title or the National Club Championship. The effort turned to presenting the Club as one of professionalism towards hosting both the Midwest Tournament as well as the National Tournament. Notice of Milwaukee RFC grew as Milwaukee advanced to be the first Club to win the National Club Championship from the Midwest. This created another layer of competitive drive for the Lions, with most players fancying their Lions as the better Club and determined to prove it. The Mike King Memorial Rugby Room was dedicated to the late Captain, who had passed earlier in the season. The next season would be a huge recruitment season for the 1985 Lions as 1986 saw flocks of young, eager players who wanted to compete for playing positions. Many of these recruitment efforts came from Paul Bergman and Jim Quigley. President Rich Joseph decided to take the young Club East in order to weather some of the newer players. They faced off two New York sides, beating the Manhattan Club and closely losing to that year's 2nd place National Finalist Old Blue. The next couple of years would be a slow build for the Lions as the 80s era was closed out with Nick Fedorenko, Sean Madden, and Pat Bulger passing the skipper's hat.

The 90s kicked off with the same work ethic and determination for success that had been set into tradition thirty years before. The 1990 season saw Kirk Soukup take the lead as captain for 91 and 92; the Lions went to the National Final 4, narrowly missing victory in 91’ and making a strong showing again in 92’. In 1993, the Chicago Lions experienced more community building than anything else, as many of the core younger men who had led the club to eleven Mid-American Cups had moved on to helping Illinois and the USA work toward expanding the game of rugby. The 93’season ended again with Milwaukee RFC defeating the Lions in the Semi-Finals of the Mid-Western Championship and not being invited to the National Tournament. The next season, 1994, the Lions made it to the semis of the Mid-Western championship again before being kicked out again. Focus again turned to hosting the National Championship at Winnemac Stadium. This drought saw no quench as the 95’ 95-season Lions saw a devastating Loss after a final battle against Palmer College for the Mid-West Championship. In hopes of reinvigorating the club, captain Mark Santiago brought the Lions squad to Northampton, England, in March of 1995. Where coincidentally, the Headmaster of the school grounds where the first-ever rugby match was played was a former Chicago Lion. This season saw many of the players graduate to CARFU or USA Rugby, and the Lions suffered in the 1996 season. 1996 was the year that saw the beginning of ideas and development of the USA Super League. This season, the Lions Club decided that their goal should ultimately be the National Championship and not to focus only on the Mid-western championship.

In 1997, the USA Super League brought an entirely new competition to focus on, as the normal Fall 15 schedule fell behind, with the Lions having to choose between the USA Super League competition and the Midwestern Championship. The Fall 15’s was still played with the normal schedule, but the Lions could not advance further than the Midwest completion, so Fall 15’s turned to friendly matches with the real bouts happening in the Spring Super League schedule. The first 1997 had the founding 14 premier clubs in the nation competing. The Lion's new head coach, Marty Wiggins, and Captain Mark Santiago quickly realized the competition they were up against as they lost all of their scheduled games. This was the trend for the next two years as the Lions finished with losing records for the 98’ and 99’ seasons.

The new century brought in fresh air for the Lions as they finished their spring season 4 and 3, their first winning record, as well as their first win on the road as they beat Philadelphia in Philadelphia. In 2001, the Lions reached the playoffs for the first time before being defeated by OMBAC in the first round. 2002, the Lions saw frustration again when they did not make it into the playoffs. Focus turned to the international match of USA vs. Canada, which would be held in Chicago, and the Lions boasted not only three players on the USA side but also a fellow Lion as the manager of the USA's rugby team. This point of pride was enough to continue pushing the Lions to work harder toward their goal of a national championship. The next year, in 2003, the Lions made it to the Semi-finals before OMBAC once again took the air out of the Lion's roar. In 2004, the Lions had an unsuccessful season and did not make it to the playoffs again. In 2005, the Lions traveled to Belmont Shore for the championship tournament. This year, they defeated Golden Gate in the quarterfinals before being knocked out by that year's national champion, Belmont Shore, in the semi-finals. The semi-finals seemed to be the LionsLion's fateful roadblock as 2006 saw OMBAC once again defeat the Chicago Lions in the Semi-finals of the playoff tournament. The Lions 7's side made it to the Finals of the National Championship but lost in the final. During the 2007 RWC, Head Coach Marty Wiggins took the Club to France to experience the spectacle in preparation for the season. The next Spring in 2007, the Chicago Lions could smell victory but lost in a close battle to Belmont Shore to become the national Super League runner-up. From 2008 through 2010, the Lions would appear in the Super League Championship but would not make it past the quarterfinal round. However, in 2010, The Lions traveled to the Las Vegas Invitational tournament, beating competition from around the nation.