The history of the Saskatchewan Roughriders dates to 1910 when they were founded as the Regina Rugby Club and became charter members of the Saskatchewan Rugby Football Union. The team changed their name to the Regina Roughriders in 1924 and became charter members of the Western Interprovincial Football Union in 1936. They began using their current moniker in 1946 and adopted it officially in 1950. The Roughriders became a charter member of the Canadian Football League when it was founded in 1958.

Although the Roughriders were not the first team to play football in Western Canada, the club has maintained an unbroken organizational continuity since their founding. The Roughriders are the fourth-oldest professional gridiron football team in existence today (only the Arizona Cardinals, Hamilton Tiger-Cats and Toronto Argonauts are older), and one of the oldest professional sports teams still in existence in North America. Of these teams, the Roughriders are both the oldest still in existence that continuously has been based in Western Canada (as well as the oldest surviving team in the CFL's present-day West Division) and the oldest in North America to continuously have been based west of St. Louis, Missouri. They are also the continent's oldest community-owned professional sports franchise, older than every American professional sports team outside baseball other than the aforementioned Cardinals (who, unlike the Roughriders, no longer play in their original city, and have moved twice in their history) and older than every Canadian sports team outside football except the Montreal Canadiens, who were founded about nine months prior to the Roughriders.

Regina dominated the SRFU prior to the establishment of the WIFU, winning all but two provincial league titles. Since the establishment of the WIFU, the Roughriders have finished first in their division eight times, but they have won the Western championship a record 28 times throughout their history. They have played for the Grey Cup 19 times, most recently in 2013 when they captured their fourth national championship.

The Roughriders played their home games at historic Taylor Field from 1936 to 2016; in 2017, the team moved to the newly constructed Mosaic Stadium at Evraz Place. The team has had 20 players inducted into the Canadian Football Hall of Fame.

Club origins, Regina Rugby Club (1910–1923)

The team was founded as the Regina Rugby Club on Tuesday, September 13, 1910, adopting the colours of old gold and purple. The team was also a founding member of the Saskatchewan Rugby Football Union as it was organized on September 22 of that year. Regina played their first game against the Moose Jaw Tigers on October 1, 1910, at the Moose Jaw Baseball Grounds where they were defeated 16–6. After going winless in their inaugural season, Regina quickly became the strongest team in the province. For the 1911 season, the team changed their colours to blue and white to match the Regina Amateur Athletic Association.

Regina went 3–1 in their second season and captured their first SRFU championship by winning a one game tiebreaker playoff against Moose Jaw. Meanwhile, the Western Canada Rugby Football Union had been formed within the three prairie provinces with the intent of creating a playoff format to determine a Western champion. Much to the displeasure of the SRFU, the Albertan and Manitoban unions had agreed to a format (ostensibly to minimize travel) in which the MRFU champion would host the Western semi-final and the ARFU champion would host the Western final. Regina balked at the prospect of playing up to two road games, and refused to participate in the inaugural WCRFU playoffs.

The Regina Rugby Club changed their colours again in 1912 to red and black. Meanwhile, the WCRFU agreed to change the playoff format so that the SRFU champion was given a bye to the Western final in exchange for the Saskatchewan champion agreeing to play the championship game on the road. Regina began an era of western football dominance. From 1912 through 1920, Regina not only won six consecutive WCRFU titles, but went undefeated in competitive play during that span. Due to World War I, no Western playoffs were held in 1916 and in 1917 and 1918 league play was halted altogether.

In 1921, the Western champion was invited to compete for the Grey Cup national championship for the first time. Regina again went undefeated in the regular season, but were required to play the Saskatoon Quakers for the provincial championship as travel difficulties had prevented Saskatoon from playing the other southern teams. Regina defeated Saskatoon, but the result was overturned after a successful protest concerning an early touchdown which had provided the decisive points. The Quakers won the rematch to mark the only time other than their inaugural season that the Regina Rugby Club did not win the SRFU championship while it was their primary competition. Ultimately, the Edmonton Eskimos traveled east to play in the 9th Grey Cup.

The team's rise to early prominence came even as it led a somewhat nomadic existence. It originally played at Dominion Park, but after the war was forced to move to the city exhibition grounds after the city sold Dominion Park. In 1921, it moved to Park Hughes on 10th Avenue in the North Central section of Regina, a rugby and soccer field built in 1910. It was the first season at an address that remained associated with the club for parts of the next nine decades.

In 1923, Regina returned to power as they won their eighth western championship over the Winnipeg Victorias and earned the right to compete in the national playoffs. The club was given a bye and advanced straight to the Grey Cup finals for the first time, but were severely outmatched, losing 54–0 to Queen's University at Varsity Stadium in Toronto. This was, and still is, the most lopsided defeat in Grey Cup history as the defending champion Queen's won their third straight national championship at the expense of the Regina Rugby Club.

Regina Roughriders (1924–1945) Following their first Grey Cup loss, the club changed their name to the Regina Roughriders in 1924 while retaining the colours of red and black. Ottawa also had a team called the Ottawa Rough Riders, but the spelling was different and the two clubs played in different leagues then (incidentally, however, both clubs shared the same colours of red and black then). The origin of the name has multiple theories, the most credible of which describes how the North-West Mounted Police were called Roughriders because they broke the wild horse broncos that were used by the force and the moniker was adopted from them. Giving credence to this theory is that during this time, the team occasionally played at the RNWMP/RCMP barracks when the then-rudimentary facilities at Park Hughes were rendered unsuitable for play by inclement weather. For a long time, the playing surface at Park Hughes was little more than dirt, and heavy rain often turned the field to a muddy bog.

An alternative, discredited story states that the name was adopted from Theodore Roosevelt's cavalry contingent that was known as the Rough Riders, who fought in the Spanish–American War. It was believed that there were Canadian troops in the contingent who returned to Canada following the war. However, this story is more often associated with the Ottawa club. While it has been suggested that some of the troops may have eventually moved out west, the Roughriders did not adopt their name until 1924, by which time the Spanish–American War was (especially in Canada) barely a historical footnote compared to the then-much more recent (and much more climactic) First World War. Following World War I, any attempt to deliberately name a Canadian sports team in honour of a unit that participated in an earlier American war would have been extremely unpopular.

During the first two years after their name change, the Roughriders failed to reclaim their western championship title, losing both times to clubs from Winnipeg. The 1926 season marked the beginning of their next reign of dominance as the club matched their own WCRFU record with seven consecutive western championships from 1926 to 1932. With dominant players such as Canadian Football Hall of Famer Eddie James, the Roughriders were a perennial contender from the West, reaching the Grey Cup finals five consecutive years from 1928 to 1932, the second-longest streak in the championship's history (the team did not challenge for the Cup in 1926 or 1927).1926 – Ottawa Senators 10, University of Toronto 71927 – Balmy Beach 9, Hamilton Tigers 6 Unfortunately, Regina remained winless in the national championship, being outscored 102–15 in those five Grey Cup games. The Roughriders won their last WCRFU title in 1934, representing the west for the seventh time in the 22nd Grey Cup, but lost to the Sarnia Imperials in that club's first Grey Cup win.

In 1928, Park Hughes was combined with Park de Young, a neighbouring baseball field, to create a much larger football venue. However, from 1929 to 1935, the Roughriders played most of their games at the larger exhibition grounds.

Western Interprovincial Football Union (1936–1958) In 1936, Regina joined the Winnipeg Blue Bombers and Calgary Bronks as the founding franchises of the Western Interprovincial Football Union, the highest level of Canadian football play in Western Canada. Also in 1936, the first permanent grandstand was built at Park Hughes and Park de Young. The Riders moved to the facility full-time that season. The stadium, renamed Taylor Field in 1946, was the Riders' home for over eight decades. The Roughriders became the first WIFU champions after they defeated the Blue Bombers and Bronks in the West Semi-finals and West Finals respectively. However, due to a rules dispute with the Canadian Rugby Union over use of their five import players from the United States, Regina was barred from competing for the 24th Grey Cup. Winnipeg had won the Grey Cup championship one year earlier with seven imports and the move to prevent Regina from competing was seen as a reaction to the previous year's western win. While the Roughriders had planned on traveling east without the five ineligible players, the CRU remained steadfast in their decision to disallow the team from competition.

The next decade in the WIFU was not as successful as the first as the team did not win another Western Final as the Regina Roughriders, nor ever finish in first place in that time span. After qualifying for the playoffs in three of their next five seasons, play from 1942 to 1944 was interrupted by World War II. While there was no regular season in 1945, the Roughriders did play the newly named Calgary Stampeders in the West Semi-finals, but lost the series two games to none.

With the folding of both clubs in Moose Jaw and Saskatoon, the Regina Roughriders became a provincially community-owned club (and has remained so since), and, consequently, changed their name to the Saskatchewan Roughriders in 1946. It is the first recorded instance of a major-league team in North America branding itself as a statewide or provincewide team. Prior to the 1948 season, the Roughriders were in need of new uniforms as their red and black ones had become old and worn out. While visiting a surplus store in Chicago, executive member Jack Fyfe found a set of green and white uniforms and purchased them for the Roughriders. Green and white have remained as the team's primary colours to this day (although the team has also worn silver and black as accent colours since then at times). The name change was made official on April 1, 1950.2009 Canadian Football League Facts, Figures & Records, Canadian Football League Properties/Publications, Toronto, Ontario, , p.282–283