The most common and most likely answer to this crossword clue is the 7 letter word HOUDINI
I've seen this crossword clue in The Times
H
O
U
D
I
N
I
More clues leading to the result HOUDINI
- Once he started his act there was no holding him
- Dog one’s fed turns tail, getting paper for magician
- He provided the ultimate in escapist entertainment
- He escaped maybe 45 minutes before policeman turned up at home
- He originally set up popular current double act: breaking free made him famous
- Nameless dog at home — one who kept escaping
- He was bound to prove entertaining
- Racket one used after short time for tie-break expert?
- Hi, I undo buckles
- He provided unconfined entertainment?
Buddy explains!

The straight part
We know that "breaking free made him famous" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case breaking free made him famous = houdini.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.