It could be, if occasional is used to mean as an amateur in a profession.
The opposite of occasional would be frequent.
Other opposites for career could be avocation or hobby.
The opposite of occasional is frequent.
Frequent.
Changeable, occasional
Some words have no perfect antonyms. "Occasional" is on a scale: Always...frequently...often...occasionally...seldom...infrequently...rarely...never. There is really no opposite. For words like this, the logical answer is to add "Not". "Not occasional" is the opposite of occasional.
Irregular. Or perhaps... Occasional.
Housewife.
Antonyms are words with opposite meanings. Occupation is a synonym (a word with a similar meaning) for career.
higher pay or contract for career and opposite for occupation
Exploring job opportunities, setting career goals, identifying skills and strengths, and creating a career development plan are all part of the Career Planning Options element in the career development planning process.
John Lennon never toured during his solo career, but made occasional appearances, most notably in Toronto and NYC.
An occasional criminal is more likely to resort to violence due to lack of experience and planning, whereas a professional criminal usually prefers to avoid violence in order to minimize the risk of getting caught and to maintain a lucrative criminal career.
Canadian born Rich Little is a famous voice actor and impressionist. He began his acting career in Ottawa Canada at Ottawa's Little Theater. Rich Little still does occasional acting and voice gigs, he is 74 years old.