The Cupertino, Cal.,-based company, which merged with Veritas last year, said Bloom will leave after an orderly transition period scheduled to be complete by the end of March.
"Gary has been a terrific partner in the merger and with the integration of the terms complete, this is a natural time for this transition," said John W. Thompson, Symantec chairman and chief executive officer. "I appreciate the dedication and passion he brought to Symantec."
Employees reporting to Bloom will now be overseen directly by Thompson. Bloom's position will not be filled at this time, Symantec said in a statement.
Bloom, former chief executive at Veritas, said in a statement that he did not regret participating in the merger.
"The strength of the management team at Symantec gives me comfort in deciding to use this transition to take a break after almost 25 years in the high technology industry," he said. "I still firmly believe in the strategic rationale for bringing Symantec and Veritas together."
Bloom had been Veritas' CEO since 2000 and chairman since 2002. Prior to joining Veritas, Bloom had held executive level positions at Oracle, most recently as the company's executive vice president.