Thomas Andrews Jr., 39, was born at Ardara House, Comber, Northern Ireland on 7 February 1873, a son of the Right Hon. Thomas Andrews and Eliza Pirrie; he was also a nephew of Lord Pirrie, principal owner of Harland & Wolff (the builders of the Titanic)

In 1884 Andrews entered the Royal Belfast Academical Institution, but at the age of 16 he left school and entered Harland & Wolff shipbuilders as a premium apprentice, gradually working his way up through various departments. He eventually became the managing director of H & W in charge of designing and was familiar with every detail of the construction of the firm's ships. In 1901 Andrews became a member of the Institution of Naval Architects, and on 24 June 1908 he married Helen Reilly Barbour; two years later a daughter, Elizabeth, was born to the young couple and they lived at "Dunallon", 20 Windsor Avenue, Belfast.

Thomas Andrews made a point of sailing with a team of mechanics on the maiden voyages of the Adriatic, Oceanic and Olympic in order to observe their operation and recommend improvements to future vessels slated to be built by his firm. It was for this very reason that Andrews planned to sail on Titanic 's maiden voyage to America, and the thirty-eight-year-old executive left his wife and daughter in Belfast while he accompanied the vessel first to Southampton and, later, out onto the vast expanse of the North Atlantic. In his final letter to Mrs Andrews he expressed his satisfaction with the new vessel:

"The Titanic is now about complete and will I think do the old Firm credit tomorrow when we sail".

Andrews boarded with a complimentary ticket No. 112050.

At sea, Andrews had spent most of the journey making notes and assisting the crew with minor difficulties as they got to know the new ship. Always a popular man on these trips Chief Baker Charles Joughin had even baked Andrews a special loaf of bread.

On the evening of April 14th, as usual, Bedroom Steward Henry Etches arrived at 6:45 to help Andrews dress for dinner which he usually took with Dr O'Loughlin the ship's surgeon. After dinner Andrews returned to his cabin (A-36) to pore over blueprints and collate his notes. Andrews barely noticed the collision and was unaware of any problem until Captain Smith sent a message requesting his immediate presence on the bridge.

Later, Saloon Steward James Johnstone described how he saw Andrews and Captain Smith touring the forward part of the ship, they visited the flooding mail room and the squash court which was also quickly filling with water. Back on the bridge Andrews broke the news to Captain Smith that in view of the damage the ship had suffered he did not expect her to stay afloat more than two hours.

During the liner's final hours Andrews wandered the decks encouraging passengers to wear their lifebelts and to make their way to the boats. He was reportedly last seen staring into space by the painting in the first class smoking room, his lifebelt discarded.