Owning what you did
“I was responsible for…”
When to use it
Describing scope. Note the preposition: responsible FOR, never "of".
What it replaces
"I was responsible of…" / "I was involved in…"
The hedged version is not wrong English. It is English that asks the interviewer to do the work of deciding whether you meant it. The confident version makes the decision for them.
In an answer
“I was responsible for the full P&L of the outlet — about 9 million a year.”
How to make it automatic
- Say it aloud five times now, at normal speed, with contractions.
- Pick one story from your own work where it fits, and say that story once using it.
- Record a 60-second answer tomorrow and listen for whether it came out on its own.