OSX – Use LaunchAgent in place of Login Items for all system users

Example with TEXTEDIT.
Drop the following into “com.myAgentName.plist” in /Library/LaunchAgents/

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
 <key>Label</key>
 <string>com.myAgentName</string>
 <key>ProgramArguments</key>
 <array>
 <string>/Applications/TextEdit.app/Contents/MacOS/TextEdit</string>
 </array>
 <key>RunAtLoad</key>
 <true/>
</dict>
</plist>

Source: STACKOVERFLOW