When we meet someone for the first time, one of the first topics discussed is what line of work they are in. We don't usually ask for their details about their birth or marriage, but rather who they work for and what kind of work they do. If this is such a large part of our lives and identities today, it certainly was for our ancestors, too.
Without learning about our ancestors' occupations, we neglect a large part of their lives. One of the easiest places to start is the U.S. Federal Census. The 1820 census and every census since 1840 has included a question about occupation. Other good sources to learn about a person's job and employer include family records, city directories, local histories, land and court records, and obituaries.
The 1820 census included questions regarding the number and nature of those involved in agriculture, commercial, or manufacturing enterprises. In 1840, the census further refined the occupational categories and asked for the number of individuals engaged in mining, agriculture, commerce, manufacturing and trade, navigation of the ocean, navigation of canals, lakes and rivers, learned professions and engineers. In 1850, the census asked for the specific occupation of every male over age fifteen. In 1860 this was expanded to include females over fifteen, and later included the number of months unemployed.
After discovering what occupations are listed in the census and comparing from year to year, you can do further research through county and local histories. For example, if a person was listed as a railroad worker, a history of the county from that time period may reveal what railroad lines ran through town, and when they were built. You could then try to find company employee records either through that company (if still extant) or through a local or state historical society. Sometimes these company records may include pictures, especially in the later twentieth century.
Other good sources for learning about an ancestors' occupation include family records such as oral or written histories, photographs, or personal papers. City directories, which were common beginning in the late nineteenth century, often list a person's occupation after their name and may tell who they work for, too. Sometimes a person has the same occupation every year but may change employers, or may work for the same company but hold different positions. It is very interesting to note these changes over a long period of time and get a general employment history for your ancestor.
Another great place to learn about an ancestor's occupation is in their obituary. Depending on the time period and the age of the deceased person, obituaries may give lengthy descriptions of their job and how long they have had it, or how long they have been retired. If someone died while still employed, this is even more likely. For example, my great-grandfather died in 1948. His obituary says he was the night telephone operator for the Southwestern Gas and Electric Company, which he had been with for 25 years, starting as an electrician with the utility firm. A local history included a picture of employees from the utility firm, and his signature was actually on the photograph (the only photograph my family has of him).
Even if we don't get quite so lucky, paying attention to our ancestors' occupations will give us a deeper perspective on their lives and may help us understand where we inherited our own interests, talents and skills.