He never did evil things such as insult, steal, or kill in the game but he slows players down, and it is implied in the game's description on the inside of the box that he is the reason King Kandy went missing.
If you have played the game you know that if you step on his space he makes players lose their precious time.
It is shown in the game that all the other candy citizens are kind and will aid you to the end of the game while Lord Licorice is known as the evil man that slows you down.
Spin off books
In many spin-off children's books, he does mean things, such as trying to eat everyone's houses (but ends up with a tummy ache).
Candyland: The Great Lollipop Adventure
In the animated special based off the 2002 version of the game, Lord Licorice has his minions (the Bites) steal Princess Lolly's scepter, and plans on using a concoction he made make Licorice grow everywhere, and take over Candyland, turning it into "LicoriceLand" as described in his musical number. They all attempt to catch the protagonists (Jib, Mr. Mint, Jolly, and Princess Lolly) but they are all foiled. After reaching to the Candy Castle, Lord Licorice tries to bring licorice to be ruler. Jib stopped him by putting green icing when trying to put the scepter. Gloppy (the swamp monster) grabs him after that. Grabbing the monarch, everyone puts their gifts on the slot (except Jib who wasted his last icing container). Lord Licorice thought he failed, but he put his backpack on the slot. Princess Lolly puts her scepter on the center slot, causing all the licorice to go away and restoring peace in Candyland. He complained that everything is lollipops and despaired he won't make everything licorice anymore (debatable).