- Captain James T. Kirk, Commander Spock, and historian Erickson use the Guardian of Forever to observe first hand Federation and Orion history. (TAS: "Yesteryear")
- Harry Mudd swindles the inhabitants of the planet Ilyra VI by trying to sell them the Starfleet Academy. (TAS: "Mudd's Passion")
- Memory Alpha's memory core is burned out, as well as all of its personnel, Federation scholars, researchers and scientist that are there at the time are killed, when the planetoid was attacked by the lights of Zetar beings. (TOS: "The Lights of Zetar")
- Lieutenant Mira Romaine begins working to restore the memory core of Memory Alpha. (TOS: "The Lights of Zetar")
- The Federation Class J space cruiser Aurora is stolen by Doctor Sevrin and his followers. (TOS: "The Way to Eden")
- The Troglyte miners of the planet Ardana start wearing filter masks to block the ill mental effects of mining zenite. (TOS: "The Cloud Minders")
- Dr. Sevrin and his followers temporarily hijack the USS Enterprise and stole the shuttlecraft Galileo II and take both into Romulan space so they could get to the planet Eden (TOS: "The Way to Eden")
- Dr. Sevrin and his follower Adam died on Eden after biting into an acid-saturated fruit. (TOS: "The Way to Eden")
- Dr. Leonard McCoy discovers that Flint, found by the USS Enterprise living on planet Holberg 917G, time as an immortal is coming to an end and he would soon die, due to his leaving Earth's atmosphere. Although not revealed during his lifetime, as an immortal Flint was known by several historic names including King Solomon, Alexander the Great, Leonardo da Vinci, Johannes Brahms, and interstellar financier Brack. (TOS: "Requiem for Methuselah")
- The USS Enterprise makes first contact with the Excalbians. (TOS: "The Savage Curtain")
- Lieutenant Arex replaced Ensign Pavel Chekov as the USS Enterprise's Chief Navigator as Chekov was assigned further officer training. (TAS: "The Magicks of Megas-Tu")
- Ensign Dawson Walking Bear, a Comanche Native American, is promoted as chief relief helmsman, for Lieutenant Sulu aboard the USS Enterprise. (TAS: "How Sharper Than a Serpent's Tooth")
- The USS Enterprise re-establishes contact with the Megans of planet Megas-Tu as the ship is exploring the galactic core. (TAS: "The Magicks of Megas-Tu")
- Lieutenant M'Ress is assigned in duty to be a relief communications officer for Lieutenant Uhura aboard the USS Enterprise. (TAS: "Mudd's Passion")
- Tuvok begins taking lessons in kal-toh from a Vulcan master. (VOY: "Alter Ego", "Gravity")
- Els Renora is born on Bajor. (DS9: "Dax")
- Keiko Ishikawa's mother is born. (DS9: "Dax")
- The Mantilles colony in the Pallas 14 system is threatened by the cosmic cloud creature. (TAS: "One of Our Planets Is Missing")
- The USS Enterprise discovers an ancient abandoned insectoid starship in orbit around Questar M-17 and makes first contact with a magnetic organism. (TAS: "Beyond the Farthest Star")
- The USS Enterprise uncovers what happened with the Terran geneticist Dr. Stavos Keniclius by finding his fifth generation clone living with the Phylosians. (TAS: "The Infinite Vulcan")
- The USS Enterprise uncovers what happened with the Terra 10 colonist, whom Earth lost contact with in the middle of the 21st century, and help their mutated Terratin descendants relocate to a geologically more stable planet than the one they are found on orbiting the star Cepheus. (TAS: "The Terratin Incident")
- A team of 127 Federation scientists, led by Professor Ketteract discovered the Omega molecule during the top secret research called "Project Omega" in the Lantaru sector. All present are killed a fraction of a second later when the molecule detonated, destroying subspace within several light years. (VOY: "The Omega Directive")
- The star Beta Niobe supernovaed destroying the planet Sarpeidon. (TOS: "All Our Yesterdays")
- The asteroid ship Yonada reaches its destination and the Fabrini settle down under the leadership of high priestess Natira. (TOS: "For the World is Hollow and I Have Touched the Sky")
- This was the beginning of the fifth and final year of Captain James T. Kirk's first five-year mission. (VOY: "Q2")
- "More Tribbles, More Troubles"
- "The Infinite Vulcan"
- "Yesteryear" (in part)
- "Beyond the Farthest Star"
- "The Survivor"
- "The Lorelei Signal"
- "One of Our Planets Is Missing"
- "Mudd's Passion"
- "The Magicks of Megas-Tu"
- "The Time Trap"
- "The Slaver Weapon"
- "Once Upon a Planet"
- "The Ambergris Element"
- "The Jihad"
- "The Terratin Incident"
- "The Eye of the Beholder"