Whitman was born to Starfleet Captain Thomas Whitman and Starfleet Science Officer Neriah Jameson, both full humans. Thomas was killed in the line of duty at the age of 64, in 2341, when Daniel was fourteen. At the time, Daniel was applying in advance for Starfleet Academy, although he did not expect to be accepted. He was not, but scored a total of 63% on the exam. Daniel was happy with this score, although he did not make it. He knew he had 4 years to perfect his skills. He joined with his mother, Neriah, for the funeral on the USS Missouri, and the two mourned the death of Thomas. Four years later, Neriah died on an away mission on Tribessia VI while serving on board the USS Bellington, an Excelsior-Class Starship. The news reached Daniel the day he received notice he had earned acceptance into Starfleet Academy, and so Daniel regards it as the best and worst day of his life.

Whitman entered Starfleet Academy at age 18, in 2349. After 4 years of Study, Whitman Graduated 5th in his class, and was voted "Most Valuable Shuttle Pilot" (a joking title), and "Most Valuable Phaser Operator" (a serious title). Instead of receiving his first posting at this time, Daniel then entered into an advanced tactical program, where advanced piloting, shuttle maneuvers, and starship maneuvers were taught. Also taught were survival tactics, advanced phaser operations, and sensor shielding techniques.

After two years of tactical training, in 2351, Daniel was assigned to the USS Constellation, a refit Constellation-class vessel. Here he served as helm officer, and, after saving the ship several times with advanced starship maneuvering knowledge, quickly earned a promotion to Junior Grade Lieutenant . In 2353, Daniel was transferred to the refit Excelsior-class vessel, the USS Yorktown, and quicky earned a promotion to Lieutenant in mid-2354 for saving the Yorktown from a hostile Klingon Vessel and was transferred to the USS Saratoga. An uneventful tenure as Chief of Helm Operations on board the Saratoga ended in 2357 after being damaged beyond repair by the Cardassians during the Cardassian/Federation War.

To aid in the war effort, Whitman was sent back to the front lines aboard the Excelsior-class USS Lakota as Chief of Helm Operations. While serving aboard the Lakota, Whitman earned his promotion to lieutenant commander. At the request of Captain James Brosnan, Whitman was transferred off of the Lakota in 2360, promoted to full Commander, and made first officer aboard the Ambassador-class USS Zhukov. As Helm officer, Whitman earned the Silver Palm with cluster, the Bronze star, and the Purple heart with cluster for his navigation and tactical knowledge in crises, as well as his bravery in the field and on away missions.

In 2364, Whitman, as a Commander, was promoted to Captain and given his first command aboard the USS Justman, a new Galaxy-class ship. After countless successful missions, Whitman was given the option of promotion to Admiral in 2370, but declined and instead continued to command the Justman. After the destruction of the Justman at the hands of the Dominion, at the request of the Starfleet Council of Defense, Whitman took command of the newly completed USS Phantom, the first of its class.