Deakin was born in St. Louis and received his degree from Washington University. In 1951, he joined the St. Louis Post-Dispatch and in 1954 was appointed to the Washington Bureau during the Eisenhower administration. Deakin has studied and reported the administrations of John Kennedy, Lyndon Johnson and Richard Nixon.
He wrote a critical report about lobbying and Lyndon B. Johnson entitled "Lyndon Johnson's Credibility Gap." He was also critical of the Nixon Administration, which landed him on the master list of Nixon political opponents.