mid-career
/mɪdkəˈrɪə/noun
1The middle of a dash or bolt.
2The middle of proceedings or a course of conduct, argument, etc.
3The middle of one's working life.
adjective
Relating to the middle of a person's working life; that has reached such a point.
Origin
Early 18th century; earliest use found in William Congreve (1670–1729), playwright and poet. From mid + career.