Naotaka was the second son of Ii Naomasa. His elder brother Naotsugu had fallen out for favor for not wishing to fight at Osaka castle and so Naotaka went in his stead. He distinguished himself at the Osaka Campaigns (commanding 3,200 men at the Battle of Tennôji in June 1615) and following their conclusion was granted his elder brother's land at Sawayama in Ômi province. He completed work on Hikone castle in 1622 (started by Naotsugu in 1603).
- Initial text from Samurai-Archives.com FWSeal & CEWest, 2005