Claremont began competing in the SCIAC in 1947-48 when Pomona College and Claremont Men’s College combined to form one athletic team (Pomona had been competing by themselves since the SCIAC’s inception in 1915). Pomona - Claremont competed in the SCIAC for 11 years and during that time its teams won 25 SCIAC titles. In 1958-59 Claremont Men’s College combined with Harvey Mudd College and began competition as Claremont-Mudd, although the team was ineligible for SCIAC championships until 1959-60. The team continued as this entity until the SCIAC began sponsoring women’s sports in 1976-77 at which time it became Claremont-Mudd-Scripps (Claremont Men's College became Claremont McKenna College in 1981). The men’s program (Stags) has won 192 SCIAC titles since its inception. The women’s program (Athenas) has won 103 SCIAC titles which is the most among SCIAC schools. Claremont-Mudd-Scripps is the only program in the SCIAC which has won at least two conference titles in each of the 21 sports. Each of the men's teams has repeated as SCIAC champion at least once and have each won at least four titles. All 11 of the women's teams have repeated as SCIAC champion as well.
The SCIAC All-Sports Competition began in 1972-73. This competition awards points to schools based on their finish in the SCIAC standings. In the 42 years of the competition Claremont-Mudd (-Scripps)’ men’s program has won the award 38 times. With the addition of the women’s programs in 1976-77 the competition was expanded to include the women’s sports as well as an overall competition. The women have won 20 All-Sports Trophies including 18 of the last 23. The combined Claremont-Mudd-Scripps athletic program has won the All-Sports Trophy 27 times with victories in 26 of the last 30 years. 2014-15 was another successful year as 11 sports won SCIAC titles and seven sports finished second or third.
Only one other school has won as many as six SCIAC men’s titles in one academic year while CMS has won six or more six times. The most men’s titles CMS has won in one year is eight in 1989-90. CMS is the only school to win six SCIAC women’s titles in one year which the Athenas achieved in 1998-99, 2010-11, and 2014-15. The combined program has won as many as 12 SCIAC titles in one year (2013-14), and has won 11 twice, 10 titles twice and nine titles six times. No other program has won more than eight in one year.
In addition to their strong showings in the SCIAC, the Claremont-Mudd-Scripps athletic program has also performed well in postseason competition. CMS has won four national championships. In 2016, the men's golf team won the golf program's first national title. In 2015, the men's tennis team won its second national championship after a tie for the title in 1981. Additionally, Claremont-Mudd won the NAIA swimming crown in 1967. The men’s swimming and tennis teams have also combined to win 13 second place trophies at the NCAA championships. In addition, men’s soccer was the NCAA runner-up in 1983. Overall, 20 of the 21 CMS sports have competed in the post-season and all 20 have finished in the top 17 including 16 in the top 10. Individually CMS athletes have won 50 NCAA titles in seven sports including men's golf, men's and women's swimming, men's and women's tennis and men's and women's track & field.
In 1995-96 the National Association of Collegiate Directors of Athletics began their Director’s Cup Competition for Division III institutions. This competition is similar to the SCIAC All-Sports competition except that points are earned based on national results rather than conference and that there are over 400 eligible schools instead of nine. Claremont-Mudd-Scripps has finished in the top 60, 18 times with 15 finishes in the top-40, 12 in the top-30, eight in the top-20 and a best of eighth (11th in the current format). These have been among the best showings by small colleges and was the best result by a SCIAC school 15 of the 20 years.