Final answer:
Richard Nixon was the first President of the United States from 1969 until his resignation in 1974, succeeded by Gerald R. Ford who served until 1977.
Step-by-step explanation:
The first president of the United States from 1969 to 1976 was Richard Nixon. Nixon was inaugurated in 1969 after winning the presidential election of 1968, a period characterized by internal dissension within the Democratic Party and societal unrest. Despite his foreign policy triumphs, his presidency was marred by the Watergate scandal, leading to his resignation in 1974, after which Gerald R. Ford then became President. Ford served the remainder of Nixon's second term until 1977 but was not elected in his own right, losing the 1976 election to Jimmy Carter.