To access LinkedIn information in Outlook 365 desktop subscriptions, you need to enable File > Options > General – at the very bottom, Enable LinkedIn features in my Office applications. Once you do this, you will be able to access LinkedIn information for people in Outlook. Hover, over an address and click the LinkedIn button on the profile card.
LinkedIn integration is available in Outlook on the web (including Outlook.com) and in Outlook 365 subscription. LinkedIn contact support requires an Office 365 mailbox and Office 365 software subscription.
If you don't have a LinkedIn account or are not signed in, you'll have less information than if you are signed into a LinkedIn account.

Paul Chidley says
"Connecting to LinkedIn from this tool is no longer support."
Your advice is out of date. Any idea how to do it now? (2019)
Michael says
Only approximately one third of my contacts are synched (after more than a week). Anywhere you can force a synchronization?
Diane Poremsky says
Are they all showing in the LinkedIn folder on Outlook on the web online?
Right click on the folder in Outlook, choose properties then look on the synchronization tab. Are the server and offline counts different? if so, switch to the general tab and click clear offline items. This will resync the folder (if it doesn't start the resync within a few minutes, click the Update folder button on the Send/Receive ribbon.)
Brandon Barber says
Hello - I just did the connector with LinkedIn, checked my Contacts folder and I am not seeing anything listed there. - Thanks
Diane Poremsky says
They will be synced to a new folder called Linkedin - it can take a few minutes to sync after enabling it.
stugoldberg says
Hi Diane,
I have some questions about archiving existing Outlook mail on my Gmail account, but my configuation has gotten so complicated that I think I need some interactive help rather than the usual forum back-and-forth.
Is there some way to get a little individualized consulting from you? Please let me know. Thanks!
Diane Poremsky says
I do one-on-one consulting. You can contact me at diane at slipstick com for more information and to schedule a meeting.