First Federal Savings and Loan Association of Alexandria has elected John T. Martyn, Jr. chairman of the board. Martyn has been a board member since 1943.

The new chairman, who has been active in Alexandria civic and community affairs for many years, is a partner in the real estate and insurance firm of Graham & Ogden, with which he has been associated since 1933.

Martyn, who also sits on the board of First Virginia Bankshares Corp., was a founding member of Mt. Vernon Bank and Trust Co.

Gurantly Bank and Trust Co. named three new directors to its board. They are Arlington lawyer John F. Carman; Fairfax businessman John B. Contristan and Guaranty executive vice president James N. Newsome.

American University president Joseph j. Sisco has been appointed to the board of the National Bank of Washington. Sisco is former under secretary of state for political Affairs.

Former Secretary of Transportation William T. Coleman, Jr. continues to receive board appointments. He has been reelected to the board of Pan American World Airways, from which he resigned in 1975 to assume his cabinet post. He has also been named to the board of AMAX, Inc.

Other board appointments of note include the election of Romulo O'Farril, Jr. to the board of Goodyear Tire & Rubber Co. and Robert S. Strauss to the Xerox board. O'Farrill, a Mexican newspaper, television and business executive, is the first citizen of a foreign country elected to the Goodyear board. Strauss is known to Washington primarily as the former chairman of the Democratic National Committee.

Fairchild Space & Electionics Co. has named John W. Townsend Jr. president and Sidney G. Miller vice president for marketing and planning Townsend has most recently been with the Commerce Department's National Oceanic and Atmospheric Administration. Miller goes to Fairchild from General Electric's space division, where he was director of marketing.

Former Assistant Secretary of Defense William K. Brehm has joined Computer Network Corp. as executive vice president. Brehm is also a former vice president of Dart Industries, Inc.

WMAL-TV has named Joseph G. Rose, Jr. as manager, finance and administration. Rose had been vice president, treasurer and chief financial officer of John Blair & Co. in New York.

Donald F. Manigold has been elected vice president for underwriting at United Services Life Insurance Co. and its subsidiaries. United Service sells insurance to the armed services and their families.