"career milestone" is correct and usable in written English.
You would typically use it when referring to a significant accomplishment in someone's career, e.g. "John's promotion to head of department was a major career milestone for him."
Yet for this career milestone appearance, Mr. Honeck stuck mainly to the staples.
A house debut is a career milestone, and Mr. Kim seemed a little nervous during Act I.
He is represented by James Cohan Gallery in New York, another prestigious career milestone for such a young artist.
A decade later, Hartofilis has reached a career milestone with the release of his first feature film, Beach Pillows.
In 1964, in another career milestone, the architect Philip Johnson commissioned an "Eat" sign for the New York State Pavilion at the World's Fair in Queens.
North by Northwest (1959) was a career milestone for both Grant and Hitchcock and is regarded as a masterful blend of suspense and humour.
The United States Open will unfold over the next two weeks, but for players like Polansky, Monday was a career milestone.
Wednesday night, he celebrated his 72nd birthday by doing what he loves, coaching his Temple Owls to a victory over Penn, and moving closer to another career milestone.
Separately, and without prompting, both Billy Gibbons and Dusty Hill recalled being invited to support the Stones in Hawaii in 1973 as a career milestone.
The grand slam gave him 1,001 runs batted in, a career milestone that Bobby Valentine thought might have been weighing on him.
The game featured the Yankees' starter, 40-year-old Roger Clemens, trying for the third time to reach a historic career milestone, 300 victories.
