He graduated from Georgia Military College with an Associate of Arts degree in 1949.

Highsmith served as chief legal advisor to the Governor's War on Crime Program from 1967 to 1968 and special counsel for the Florida Racing Commission from 1969 to 1970.

[1] On June 27, 1991, President George H. W. Bush nominated Highsmith to the United States District Court for the Southern District of Florida, to the seat vacated by Judge Thomas Scott.

Highsmith assumed senior status on March 15, 2002, but stopped hearing cases in 2008.

He died on December 2, 2015, at his family's home in Fort Belvoir, Virginia, from the effects of Alzheimer's disease.