The phrase 'subsequently becoming' is correct and usable in written English.
You can use it to describe a situation in which something occurs at a later time after something else has happened. For example: After gaining a degree in marketing, Beth took a series of internships, subsequently becoming a successful advertising executive.
Pratchett immediately donated $1m to Alzheimer's Research UK, subsequently becoming a patron.
Later in development, Bowman's capsule arises as a diverticulum of each tubule, subsequently becoming indented by the glomerulus.
Tringale, 43, says his life changed for ever following a brutal gang rape, that led to him going AWOL from the army, and subsequently becoming homeless.
She was appointed the New York Philharmonic's assistant conductor in 2002, subsequently becoming their associate conductor and the first holder of the Arturo Toscanini chair.
They met in the 1940s through their involvement in a ground-breaking gay rights magazine and subsequently becoming embroiled in a vicious gay hate crime.
After obtaining a teacher's higher education certificate in 1946, Nzekwu taught for nine years, subsequently becoming editorial assistant and then editor of Nigeria Magazine in 1962.
In Britain it failed to register until 1969, when it was reissued and reached the top 10, subsequently becoming acknowledged as one of the very finest pop records of its era.
He first worked with Fairport Convention in 1969 as a session musician, subsequently becoming a member of the group, and was the first fiddler on the UK folk scene to electrify the violin.
Speaking to Josie Dobrin, who co-founded the charity back in 2012, alongside talent agent Michael Foster, she says that funding was almost secured until the Brexit vote and Theresa May subsequently becoming prime minister.
Given she is the daughter of the CEO of Hustler magazine and was chucked out of home when her parents found out she was gay, subsequently becoming a stripper, she had probably exhausted the outrageous route.
