Jenkinson is highly rated within the current setup at parent club Arsenal but not enough to be given a starting berth in Arsene Wenger's main XI.
As such, the 23-year-old was wary of another season spent on the bench when the Gunners brought Mathieu Debuchy to north London in the summer.
That's when the 'big decision' of leaving on loan came into play for Jenkinson - and he is delighted he chose to join West Ham.
“It was a big decision,” the Arsenal loanee admits. “But [Mathieu] Debuchy came through the door for £12m, and I kind of knew a club doesn’t pay that money for a player and not play him.
"I didn’t want another season of just sitting on the bench, so I spoke to the boss and he agreed it would be a good idea for me to get a season of experience under my belt in the Premier League.
"It’s definitely been the right decision for me. It’s been the first time I’ve played regular football week in, week out, and that’s all a footballer really wants to do.”
Despite Jenkinson's promising campaign at West Ham, the Hammers' high standards from earlier this season haven't been maintained by Sam Allardyce's men.
As a result, the east London side are now under serious threat of finishing in the bottom half of the Premier League - a far cry from when they sat fourth in the standings.
The alarming slide has led to ever-increasing speculation about Allardyce's future, with the 60-year-old's contract up at the end of the current campaign. Could his departure, though, have any bearing on whether Jenkinson joins West Ham full-time or stays at Arsenal beyond this term?