Job
A job was the task an individual did on a daily basis.
The Doctor
The Eleventh Doctor claimed that he would be brilliant at having a job. He considered his duties as UNIT's scientific advisor to be his job, though Clara Oswald doubted that he could ever hold a job. (TV: The Day of the Doctor)
Across their many incarnations, the Doctor held various jobs, usually for the purposes of their investigations. The Tenth Doctor took a job as a teacher to investigate the oddities at Deffry Vale High School. (TV: School Reunion) The Eleventh Doctor briefly held a job at Sanderson & Grainger, a department store in Colchester. Though he claimed he did so to "live in the moment", he was actually investigating Cyber-activity which seemed to be localised around his new workplace. (TV: Closing Time) The Twelfth Doctor worked as a lecturer at St Luke's University since the 1940s (AUDIO: Regeneration Impossible) as he and Nardole guarded the Vault. In 2017, he took on the additional job of being Bill Potts' personal tutor. (TV: The Pilot)
In an alternate timeline caused by a temporal collision, the First Doctor spent three months working as a guest lecturer at a university in Kiria City on Urbinia. (AUDIO: Daughter of the Gods)
The Doctor's companions
The Doctor's first two human companions, Ian Chesterton and Barbara Wright, were teachers at Coal Hill School, teaching science and history respectively. (TV: An Unearthly Child) By 2010, the two were employed at the University of Cambridge. (TV: Death of the Doctor) Liz Shaw also taught at Cambridge. (AUDIO: Primord)
In an alternate timeline caused by a temporal collision, Steven Taylor spent three months working at a spaceport in Kiria City on Urbinia. (AUDIO: Daughter of the Gods)
Sarah Jane Smith worked as a journalist. (TV: The Time Warrior)
Prior to her travels with the Doctor, Rose Tyler worked as a shop girl in Henrik's before the Ninth Doctor blew up the building. Before she could find a new job, she joined the Doctor in his travels. (TV: Rose) During their investigation of Deffry Vale High School, Rose was forced to work as a lunchlady. (TV: School Reunion)
When the Doctor and Martha Jones were stranded in 1969, the latter was forced to work at a shop. (TV: Blink, COMIC: A Little Help from My Friends) After leaving the TARDIS, Martha was employed by UNIT. (TV: Reset) Some time after the Planetary Relocation Incident, she left UNIT to become a freelance alien hunter alongside Mickey Smith. (TV: The End of Time)
Donna Noble's career consisted mainly of temp jobs. (TV: The Doctor's Daughter) After leaving the Doctor, Donna had taken a new job in 2009, one that Wilfred Mott felt did not pay enough to ensure her financial independence. (TV: The End of Time)
Amy Pond held multiple jobs during her time travelling with the Eleventh Doctor. She initially worked as a kissogram, (TV: The Eleventh Hour) before changing jobs to become a model, (TV: Closing Time, Asylum of the Daleks) a writer for a travel magazine (TV: The Power of Three) and finally a fiction author. (TV: The Angels Take Manhattan, The Bells of Saint John) By contrast, her husband Rory Williams kept his job as a nurse throughout his life. For his part, the Doctor was shocked that both of them had jobs, having assumed that the couple mainly kissed when he was not there. (TV: The Power of Three)
Clara Oswald initially worked as a nanny, (TV: The Bells of Saint John) before she became a teacher at Coal Hill School. (TV: The Day of the Doctor) She later transferred to Ravenscaur School. (TV: Clara Oswald and the School of Death) Not long after the Twelfth Doctor's regeneration, Clara noted to him that their travels were her hobby, not her job. (TV: Into the Dalek)
Yasmin Khan was a police officer employed at Hallamshire Police when she met the Thirteenth Doctor. (TV: The Woman Who Fell to Earth) Though she was initially heavily dedicated to her profession, to the point that her family considered her to be "married to her job", (TV: Arachnids in the UK) her increasing association with the Doctor caused her to she leave this profession sometime before the First Flux event. (TV: The Halloween Apocalypse)
Graham O'Brien was once employed as a bus driver, but had retired prior to becoming a companion of the Thirteenth Doctor. (TV: The Woman Who Fell to Earth, Rosa)
Others
Lavinia Smith was a world-renowned virologist in the late 20th century. (TV: The Time Warrior)
In 2008, Tish Jones got a PR job at Lazarus Laboratories, (TV: The Lazarus Experiment) which was secretly arranged by the Saxon Master. Later, having been "phoned up" "out of the blue", Tish Jones got a job at 10 Downing Street on the Master's first day as Prime Minister of the United Kingdom. (TV: The Sound of Drums)