Former ambassadors representing every president since Franklin D. Roosevelt said yesterday that they "deplore" last week's political endorsement of Sen. Jesse Helms (R-N.C.) by 22 of President Reagan's ambassadors.

"This action violates a well-established tradition followed by administrations of both parties which has barred . . . ambassadors, noncareer as well as career, from engaging in partisan politics while on active duty . . . ," said the statement, signed by 36 former ambassadors.

Those signing the letter include W. Averell Harriman, ambassador to the Soviet Union under Presidents Roosevelt and Harry S Truman; Jacob D. Beam, ambassador to Poland under President Dwight D. Eisenhower and to the Soviet Union under President Richard M. Nixon; George W. Ball, United Nations ambassador under President Lyndon B. Johnson; Patricia Roberts Harris, Luxembourg, under Johnson; Martin J. Hillebrand, West Germany, under Nixon and President Gerald R. Ford; Donald F. McHenry, U.N., under President Jimmy Carter and William van den Heuvel, U.N., under Carter.

About a third of those who signed the statement served as career Foreign Service officers. The 22 envoys who endorsed Helms are not Foreign Service officers and not subject to federal employes' limits on political activity.

The letter also said the action was "regrettable, because Jesse Helms has been one of the most consistent opponents in . . . Congress of sound foreign policy development during the last 12 years."

An aide to Helms, who is in a tight reelection battle with North Carolina Gov. James B. Hunt, has said the endorsements show the senator is in accord with Reagan's foreign policy. State Department officials said that they discourage political activity by ambassadors, but that the endorsements were individual decisions and legal.

Philip M. Kaiser, who was ambassador to Senegal in the Kennedy administration and also served under Carter, said the 36 signatures were obtained in one day.

"We were disturbed, distraught, distressed and appalled about it," Kaiser said.

Other former ambassadors who signed the letter are:

Gardner Ackley, Italy, 1968-69; Eugenie M. Anderson, Denmark, 1949-53; William Attwood, Guinea, 1961-63, Kenya 1964-66; Lucius D. Battle, Egypt, 1964-67; Maurice Bernbaum, Ecuador 1960-64, Venezuela, 1965-69; L. Dean Brown, Senegal and Gambia, 1967-70, Jordan, 1970-73; Harlan Cleveland, NATO, 1965-69; Richard N. Gardner, Italy, 1977-81; Robert F. Goheen, India, 1977-81.

Also, Lincoln Gordon, Brazil, 1961-66; William J. Jorden, Panama, 1974-78; Geri M. Joseph, the Netherlands, 1978-81; Philip M. Klutznick, 1961-63; Edward S. Martin, Argentina, 1964-68; John Bartlow Marin, Dominican Republic, 1962-64; Gale W. McGee, Organization of American States, 1977-81; George C. McGhee, Turkey, 1951-53, West Germany, 1963-68; David H. Popper, Cyprus, 1969-73, Chile 1974-77; Edwin O. Reischauer, Japan, 1961-66; Richard L. Sneider, Korea, 1974-78.

And Carl P. Rowan Jr., Finland, 1963-64; J. Robert Schaetzel, European Communities, 1966-73; Ben Stephansky, Bolivia, 1961-63; Phillips Talbot, Greece, 1965-69; Roger Tubby, European Offices of the U.N., 1962-69; John W. Tuthill, European Communities, 1962-66, Brazil, 1966-69; Jack Hood Vaughn, Panama, 1964-65, Colombia, 1969-70; Murat W. Williams, El Salvador, 1961-64.