Having led the west Londoners' reserve team to the national championship in 2011, the 43-year-old joined Andre Villas-Boas' backroom staff during the Portuguese's time at Chelsea as assistant first-team coach.
It is a role he has continued under Roberto Di Matteo, Rafael Benitez and now Mourinho.
Holland is also working as assistant to Under-21s boss Gareth Southgate - a role he is thankful to the current Blues boss for allowing him to take up.
"Jose has always been very supportive of England and the national teams at all levels and he was very supportive of me coming," Holland told www.thefa.com.
"There's only five players left at Chelsea over this 10-day block because all of our players are involved in European competition, so it is a quiet time where I can be missed without there being any sort of issue.
"It's been a fantastic experience and they're all good guys and good to work for, which is why they get to the top.
"They all have a slightly different way of doing things, whether that's man-management, organisation or tactical and technical aspects.
"But it's been a great learning curve for me to be able to tap into those minds and look at what's succeeded and perhaps what hasn't succeeded to learn from that myself."
Holland first joined up with the Young Lions for last month's European Championship qualifiers against Moldova and Finland, following which it was announced he will join Southgate's staff for the remainder of the build-up to the tournament in 2015.
"I've really enjoyed it so far, I've got to know Gareth and he's a good guy to work for and the players have been really receptive with a good attitude towards their work," he said.
"From a personal point of view, I really enjoyed the last get-together and we're only a couple of days into it this time, but you can feel yourself developing those relationships and getting to know people more and more."