Claremont Men’s College began competing in the SCIAC in 1947–48 after combining with Pomona College to form one athletic team. (Pomona College had been competing since the SCIAC’s inception in 1915.) Pomona-Claremont competed in the SCIAC for 11 years and during that time won 25 SCIAC titles. In 1958–59 Claremont Men’s College combined with Harvey Mudd College and began competing as Claremont-Mudd, although the sports teams were ineligible for SCIAC championships until 1959–60. The program 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 was renamed Claremont McKenna College in 1981.) The men’s program (Stags) has won 209 SCIAC titles and the women’s program (Athenas) has won 128 SCIAC titles—both the most among SCIAC programs.
The SCIAC All-Sports Competition began in 1972–73. This competition awards points to programs based on the finish of each sport in the SCIAC standings. In the 46 years of the competition the CMS men’s program has won the award 41 times. With the addition of the women’s sports in 1976–77, the competition was expanded to include a women’s award as well as an overall award. The CMS women’s program has won 24 All-Sports Trophies including 22 of the last 27. Claremont-Mudd-Scripps has won the combined All-Sports Trophy 31 times with victories in 30 of the last 34 years. The 2018-19 year was another successful one for CMS as 12 sports won SCIAC titles.
The most men’s titles CMS has won in one year is eight during 1989–90, while the Athenas matched that total with eight titles in 2018-19. CMS is the only program to win six or more SCIAC women’s titles in one year which the Athenas achieved in 1998–99, 2010–11, 2014–15, 2016-17, 2017-18 and 2018-19. The combined program has won as many as 14 SCIAC titles in one year (2016–17).
In addition to a strong showing in the SCIAC, Claremont-Mudd-Scripps has also performed well in postseason competition. CMS has won seven national championships (either NAIA (1), or NCAA D-III (6). In 2017, the women’s volleyball team won its first national title, which was also the first NCAA women’s team title in CMS history. That same academic year, women's golf and women's tennis both won their first national championships to give the Athenas three championships in one year. In 2016 the men’s golf team won its first national title, while 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 14 second-place trophies at the NCAA Championships. In addition, men’s soccer was the NCAA runner-up in 1983. Individually, CMS athletes have won 58 NCAA titles in eight sports including men’s and women'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 Directors’ Cup Competition for Division III institutions. This competition is similar to the SCIAC All-Sports competition except that points are earned based on national rather than conference results and there are over 400 eligible programs instead of nine. Claremont-Mudd-Scripps has finished among the top 60 programs 21 times with 18 finishes in the top-40, 15 in the top-30, 12 in the top-20, three in the top-10, and most recently a program-best third place finish for the 2017-18 season.