Lynn Loud, Sr. (or Dad) is the father of Lincoln Loud and his sisters.
Lynn Sr. is stern, and often calls a halt to his kids' fights, but he loves and cares about them. He also loves his wife, and often acts playfully romantic towards her. He has been shown to have a childlike side at times, even sometimes taking part in his kids' antics, when it's all in good fun. He's also the more sensitive of the two parents, often necessitating his wife, and stepping in whenever he needs to pull himself together.
He's usually a good parent but two times he was shown as an abusive parent as in "April Fools Rules", he agreed to lock Luan in crate to prevent her from pulling harming pranks, and in "No Such Luck", he believed Lincoln is bad luck so he expelled him from house and disowned him by selling his furniture like he didn't expect him to return.
His personality is very similar to that of Tom Harper from Nicky, Ricky, Dicky & Dawn, as well as Harold Buttowski from Kick Buttowski: Suburban Daredevil, who are also father characters played by Brian Stepanek.
It is revealed in "House Music" that he used to be in a band, but got kicked out due to playing his cowbell too much, even when they were not practicing.
In "Fed Up", it is revealed that Lynn Sr.'s astrological sign is Libra, which means he was born on or somewhere between September 23 and October 22.
The colors and styles of clothing that the Loud and McBride parents wear correspond with each other. Lynn Sr. and Harold both wear sweaters, and brown loafer shoes. They also both have thinning hair.
↑20 July 2016 Overnight Success/Script: (Dad) "AH! Lynn Junior!" 15 September 2016 post on the official Loud House Instagram account: What's your favorite food - it's a toss-up between my Lynn-sagna, my Lynn-guini and my Lynn-til soup!