Over the years I've had a few occasions where I had the need of taking an RSS feed and importing it into a separate WordPress blog and auto-publishing each RSS feed item.
On ConcealedCarry.com we have a Podcast Network which at the time of this writing includes 4 different podcasts. We want to have a “home” website for the entire network which automatically displays recent episodes from all the different podcasts.
You might have a different reason for wanting to import content from one blog into another but be cautious. Duplicating content from one site to another will have a negative SEO impact on both websites. On the other hand if you, like in my above example, just need to display content titles, images, and excerpts but ultimately want those posts to link back to the origin site that can be an effective strategy.
Out With The Old
Over the years I've tried a few different WordPress plugins. For a time I was using “Autoblog” which came from the WPMU development team. It has since been retired and is no longer developed or supported. If you are using Autoblog you need to dump it and move on.
I also spent some time using WPeMatico. WPeMatico is a freemium plugin with decent free features. For me, it was inconsistent and unreliable. You might have better luck.
Enter The King: WP RSS Aggregator
For many many years I've been using WP RSS Aggregator. It is also a freemium plugin and I would encourage setting up and using the free plugin before you commit and purchase the Pro version.
I've been impressed with the reliability. Without fail, assuming WordPress cron is running (and it should be default) this plugin has never failed to properly import for me.
It has a lot of great features. I appreciate the options relating to featured images, update interval, import order, and import limits.
I've spent my fair number of hours working through these different solutions so hopefully you won't have to. Give WP RSS Aggregator a try.