Software engineer Jesse Severe says he can pretty much throw a dart on a map and find a job. The 41-year-old from San Diego says he's contacted by headhunters at least once a month, at times has been able to work from home for half his workweek and makes a comfortable living.

All those factors and others landed software engineer in the No. 1 spot on a newly-released study of the 200 best and worst jobs by CareerCast.com, a career website owned by Adicio Inc. (Until last year, Wall Street Journal owner News Corp. held a minority...