1901
• Second chapter established at Columbia University, called Morningside (Beta)

1902
• Delta Sigma Phi incorporated in New York state on December 15

1903
• Third chapter informally established at New York on December 15
• First national Fraternity dinner held December 26

1904
• Formal installation of University Chapter January 2

1905
• Constitutional Convention held in August at Insula' apartment
• Charles A. Tonsor, Jr. elected president, and Meyer Boskey elected secretary
• The Convention adopted a Constitution that created national offices and an executive committee to govern between Conventions
• Two new chapter formally received into the Fraternity during the Convention: Technology (Delta), which had been organized at the Massachusetts Institute of Technology in 1904; and Keystone (Epsilon), organized in 1905 at Penn State

1906
• Tonsor and Boskey chartered the Washington and Lee Chapter as Stonewall (Zeta)
• First alumni group chartered as the New York Alumni Chapter
• The Convention changed the Fraternity's approach to naming chapters to the present Greek-alphabet designations

1907
• Boskey, having conceived the idea of a national magazine to bind the chapters together, published the first issue of The Carnation in April
• Eta Chapter installed at Texas
• Theta Chapter installed at Cornell

1908
• Official badge designated at the convention
• Kappa Chapter established at Alabama Polytechnic Institute (Auburn) in November
• Iota Chapter installed at Penn in December

1909
• Lambda Chapter installed at Trinity
• Delta Sigma Phi became a founding member of the National Interfraternity Conference

1910
• Mu Chapter installed at Chicago
• Nu Chapter installed at Waynesburg

1912
• Omicron Chapter installed at Cumberland
• Convention created an Administrative Council with the power to grant chapters between Conventions

1914
• Office of national general secretary created at the Convention and Arthur Defenderfer chosen to fill the position
• The Ritual first published
• Fraternity restricted membership to men of the Christian faith
• Coat-of-arms, seal, pledge symbol, and badge adopted

1915
• First Delta Sigma Phi Headquarters opened in the Reibold Building, Dayton, Ohio
• Hilgard Chapter installed at UC-Berkeley
• Pi Chapter installed at Furman
• Rho Chapter installed at NC State
• Sigma Chapter installed at Thiel
• Tau Chapter installed in Hillsdale
• Upsilon Chapter installed at Franklin and Marshall
• The Carnation is named the official magazine of the Fraternity

1916
• Phi Chapter installed at St. Louis
• Chi Chapter installed at Tulane
• Psi Chapter installed at Wofford
• Omega Chapter (the last of the single Greek letter charters) installed at Pitt
• The Convention divided the nation into geographical districts, established a system of district deputies to supervise each one

1919
• Convention made biennial instead of annual
• First deputy district system established

1920
• Lon A. Scott, who had graduated from Cumberland University in 1915 as valedictorian of his class, became Delta Sigma Phi's first congressman

1921
• The Convention established Board of Governors of seven men with full power to manage and direct the affairs of the Fraternity; the Board of Governors later shrank to five members, and the Administrative Council disappeared, replaced by an Endowment Board of Trustees

1922
• On May 23 a trademark was granted to Delta Sigma Phi for the quarterly, The Carnation

1923
• The Sphinx, an esoteric publication, first appeared; it has been issued subsequently as needed
• The Convention adopted a ceremony for the dedication of new chapter houses and instituted the Pilgrim Degree, a special ritual for those making the pilgrimage to a national Convention
• The Fraternity initiated its first and only honorable member of the Fraternity when the Honorable James J. Davis, secretary of Labor in the Harding, Coolidge, and Hoover cabinets, was initiated at the request of Omega Chapter
• At the Fraternity's quarter-century mark, there were forty undergraduate chapters

1925
• First pledge manual issued; now called the Gordian Knot

1926
• Board of Governors adopted official Fraternity flag
• The first Sailors Ball held at Alpha Chi Chapter

1928
• First Fraternity Manual published

1929
• Fraternity reincorporated in the District of Columbia, where the offices of General Secretary Defenderfer were located

1931
• Harvey H. Herbert Award for distinguished service to the Fraternity first awarded

1932
• The Lute Songbook first published

1936
• First district training school for officers conducted in Chicago

1938
• Board of Governors banned Hell Week practices throughout the Fraternity

1940
• Upon the retirement of Arthur Defenderfer, the Headquarters moved from Washington, D.C., to Springfield, Ohio, the home city of Arthur Sprague, the new national treasurer
• Marcus E. Sharpe became executive director

1942
• Arthur H. Sprague became executive director

1946
• Harold Balback became executive director

1947
• System of universal life membership approved, providing The Carnation to each initiate as a life subscription
• Francis Wacher became executive director

1948
• Twelve chapters installed-the largest number in the history of the Fraternity-two revived

1949
• Deputy district system gave way to an eighteen-member governor system

1950
• Headquarters moved to Denver
• New flag chosen

1951
• The Delta Sigma Phi Foundation established; granted status as a nonprofit educational Foundation in 1958, it provides scholarships to students with high academic achievement and supports other Delta Sigma Phi educational programs

1954
• The Lute Songbook reissued

1959
• Delta Sigma Phi votes to end racial and religious discrimination policies (though the policies had not been enforced for much of the time they were in effect)

1961
• Office of executive secretary renamed executive director

1965
• Outstanding Active Award established

1967
• The Grand Council formed
• Governor system redesigned to reflect the earlier deputy district system

1969
• Mr. Delta Sig Award, the highest honor the Fraternity can bestow, first conferred
• Denver Headquarters moved to Milwaukee Street

1978
• Following retirement of Francis Wacker, E. Allen James became executive director

1982
• Headquarters moved in Indianapolis, Indiana

1983
• Taggart Mansion purchased, renovation completed in 1984

1984
• Delta Sigma Phi became the first organization to provide fraternity experience to deaf students by establishing a colony at Cal State-Northridge

1985
• Pyramid of Excellence implemented, a new award structure for recognizing the top chapters in the Fraternity
• Delta Sigma Phi became the first fraternity to ban Little Sister organizations

1987
• Outstanding Active Award renamed the E. Allen James Outstanding Undergraduate Award upon James's retirement as executive director
• David A. Testerman became executive director

1988
• Risk Management Policy adopted, prohibiting use of chapter funds for purchase of alcohol

1989
• Daniel A. Smercina became executive director
• Largest Convention attendance ever (held in Washington, D.C.)

1991
• Regional Leadership Director program introduced to replace leadership consultants

1993
• First College of Engineered Leadership; held at Purdue
• Alumni Recognition Ceremony adopted

1994
• Austin Hastings became first undergraduate member of the Grand Council in January

1996
• Delta Sigma Phi launches Internet home page on the World Wide Web

1997
• Tony Smercina is appointed the executive director of the Foundation - Jon Hockman becomes the executive director of the Fraternity

1998
• College of Engineered Leadership changes to the Leadership Institute
• The Challenge Team replaces the Regional Leadership program

1999
• The 52nd Biennial Convention assembled voted to adopt The Challenge initiative effective December 10, 2000
• Delta Sigma Phi celebrates the 100th Anniversary of the Fraternity