William Behrens was born on September 14, 1922, in Newport, Rhode Island. He entered the U.S. Naval Academy with the class of 1944 in June 1940, but was graduated a year early, in June 1943, because of the demands of World War II. After graduating from submarine school, Behrens served two war patrols aboard the submarine USS Sandlance (SS-381) and then four war patrols aboard the USS Picuda (SS-382). He served as engineering officer aboard the submarine USS Quillback (SS-424) from July 1946 to August 1948, and then as Executive Officer, Operations Officer, and Navigator on the USS Clamagore (SS-343) from September 1948 to March 1950. Behrens served as an instructor at the U.S. Fleet Sonar School from 1950 to 1952, and then served as Executive Officer aboard the USS Odax (SS-484) from 1952 to 1953. His first command was aboard USS Balao (SS-285), where he served from 1953 to 1954, before taking command of USS Harder (SS-568) from 1954 to 1955. He next served at the submarine school as head of the engineering department before being assigned as the Director of the first Nuclear Power School, where he served until 1957. Behrens then served at the Naval Reactors Branch from March to December 1957, and then oversaw the construction and commissioning of the submarine USS Skipjack (SSN-585) from January 1958 to December 1960. He attended the Polaris Command Course at the Guided Missile School from January to March 1961, and then took command of the ballistic missile submarine USS Ethan Allen (SSBN-608), where he served from March 1961 to May 1963. Behrens attended the National War College from 1963 to 1964, and then served with NATO from August 1964 to January 1966. He next served on the Policy Planning Council in the Department of State from January 1966 to August 1967, and then became commander of Amphibious Group ONE, where he served from August 1967 to July 1969. During this time, he participated in 28 amphibious operations in the Vietnam War. ADM Behrens was appointed Director of Politico-Military Policy in July 1969, and then became Oceanographer of the Navy in September 1970. During this time he helped create the National Oceanic and Atmospheric Agency (NOAA). ADM Behrens became Deputy Administrator of NOAA in 1972, and served in this position until his retirement from the Navy in August 1973. He married the former Betty Ann Taylor of Tampa, Florida, in 1946, and they had five children; Elizabeth, William III, Richard, Charles, and Susan. William Behrens died on January 21, 1986, and was buried at Arlington National Cemetery. His wife of 40 years followed him in death on May 5, 2005, and was buried in a common grave at Arlington with William and their 5 year old son, Richard, who had died in 1957.

His Silver Star Citation reads:

For gallantry and intrepidity in action in the performance of his duties as Communication Officer aboard a United States Submarine during a war patrol of that vessel. His skillful supervision and co-ordination of communications throughout the ship, and his inspiring leadership of communications personnel, assisted his Commanding Officer appreciably in conducting successful torpedo attacks which resulted in sinking enemy vessels totaling more than 18,000 tons and damaging in excess of 8,500 tons. His coolness and devotion to duty contributed materially to the success of his vessel. His conduct throughout was an inspiration to the officers and men in his ship, and in keeping with the highest traditions of the United States Naval Service.