The Sioux is a cavalry based civilization with very powerful and balanced cavalry but mediocre infantry units. Defensive capabilities of the Sioux are limited as they cannot build walls.
The Sioux economy does not requires Houses for population and is very natural resource dependant, as that is where almost all of their economy cards focus, making them excel in maps where such are plentiful. In the early game players should aim to gather mostly Food in order to procure more villagers, as the Sioux have one of the fastest times to reach maximum villager count of all civilizations.
Late game Sioux economy is weak when compared to other civilizations due to their severe lack of farm and plantation oriented cards, putting them at a disadvantage in longer games.
One of the biggest advantages the Sioux have are their Teepees. Once all related cards are used, teepees can research European arsenal unit upgrades, boost unit HP and attack within a small range, cost 35 wood and are built very quickly. Hitpoint and attack boosts of several teepees stack, and with a build limit of 20, teepees easily make Sioux units much stronger than they are. Through the use of another card, War Hut units can build War Huts, Teepees and Stables, giving the Sioux military a mobility advantage similar to the ones possessed by Japanese Daimyos and Ottoman Janissary. Coupled with the Fire Dance, Sioux units can almost reach artillery level siege attack.
Sioux troops are weak against enemy Pikemen and Musketeers, so to counter these units the Sioux can train some Wakina Rifles, some Cetan Bows or Rifle Riders are also useful against them. To be successful in attacks, the Sioux should make their attacks short and quick. A good way the Sioux could attack is to use a large group of cavalry led by a War Chief (boosting speed and attack with a card), the Sioux should also spot weak spots in the enemy civilization's economy and attack and harass the enemy there constantly.
The Sioux have a large selection of Cavalry Units to use. It is best to use the diverse Cavalry when playing as the Sioux. Although it is not heavily advised, a Sioux player can train an all cavalry army and it would still be quite balanced. Ranged infantry can be countered by Axe Riders, Dog Soldiers, and Tashunke Prowlers. Heavy infantry can be beaten with Dog Soldiers and Rifle Riders. Cavalry can be destroyed with Bow Riders and Rifle Riders and artillery can be countered with any unit. Since they don't need to build houses they are great at rushing since the resources and time spent on houses can be diverted to building an army.
The Sioux navy is average since they are the only Native American civilization to lack the Water Dance. However they make up this through the Fire Dance which increases siege damage of units, allowing their Canoes to handle other ships with relative ease.
The Sioux are good at rushing, since they start with 200 population and their Colonial Age infantry costs Food and Wood, as opposed to Food and Coin. This means that they can use their Wood on a War Hut and War Clubs or Cetan Bows, instead of spending these precious recourses on Houses. While this may seem like a small advantage, it is surprising how a few hundred wood can change the game.