Before becoming an astronaut, Cernan graduated with a bachelor of science degree in electrical engineering from Purdue University in Indiana, and joined the U.S. Navy through the Naval Reserve Officers Training Corps (NROTC).

[7] Cernan was commissioned a U.S. Navy Ensign through the Naval Reserve Officers Training Corps (NROTC) at Purdue, and was initially stationed on the USS Saipan.

[8]: 29–31  Following flight training on the T-28 Trojan, T-33 Shooting Star, and F9F Panther, Cernan became a Naval Aviator, flying FJ-4 Fury and A-4 Skyhawk jets in Attack Squadrons 126 and 113.

[9] In October 1963, NASA selected Cernan as one of the third group of astronauts to participate in the Gemini and Apollo space programs.

This provided NASA planners with critical knowledge of technical systems and lunar gravitational conditions to enable Apollo 11 to land on the Moon two months later.

Apollo 10 holds the record for the highest speed attained by any crewed vehicle at 39,897 km/h (24,791 mph) – more than 11 km per second — during its return from the Moon on May 26, 1969.

During the three days of Apollo 17's surface activity (11-14 December 1972), Cernan and Schmitt performed three EVAs for a total of about 22 hours of exploration of the Taurus–Littrow valley.

Their first EVA alone was more than three times the length astronauts Neil Armstrong and Buzz Aldrin spent outside the LM on Apollo 11.

During this time, Cernan and Schmitt covered more than 35 km (22 mi; 19 nmi) using the Lunar Roving Vehicle and spent a great deal of time collecting geologic samples (including a record 34 kg (75 lb; 5.4 st) of samples, the most of any Apollo mission) that would shed light on the Moon's early history.

[9] In 1981 and 1982, Cernan joined Frank Reynolds and Jules Bergman on the extensive ABC coverage of the first 3 Space Shuttle launches.

From 1987 he was a contributor to ABC News and the weekly segment of its Good Morning America program titled "Breakthrough", which covered health, science, and medicine.

[17] In 1999, with co-author Donald A. Davis, he published his memoir The Last Man on the Moon, which is about his naval and NASA career.

Cernan and Neil Armstrong testified before U.S. Congress in 2010 in opposition to the cancellation of the Constellation program, which had been initiated during the George W. Bush administration as part of the Vision for Space Exploration with the aim of returning humans to the Moon and eventually Mars, but was deemed underfunded and unsustainable by the Augustine Commission in 2009.

Eventually, Cernan was won over and signed the photograph; "As I told him these stories of heroic entrepreneurship, I could see his mind turning."

[42] In the 1998 Primetime Emmy Award-winning HBO miniseries From the Earth to the Moon, Cernan was portrayed by Daniel Hugh Kelly.

[43] The audio commentary for the Criterion Collection release of the film For All Mankind was recorded by Cernan and director Al Reinert in 1999.

He states in the 2014 documentary The Last Man on the Moon[46] that he wrote them in the lunar dust as he left the rover to return to the LM and Earth.

[47] The true story of leaving the initials on the lunar surface was prominently mentioned in "The Last Walt", a 2012 episode of Modern Family.

[48] A recording of Cernan's voice during the Apollo 17 mission was sampled by Daft Punk for "Contact", the last track on their 2013 album Random Access Memories.

The fictional main character draws comparisons to and shares similarity with the commander of the Apollo 17 mission, Gene Cernan.