How are sports teams schedules made?

In the NHL, each team plays either four or five games against the other teams in its division (a total of 26 or 29 games in the Western Conference, 28 games in the Eastern Conference) as well as playing all non-divisional teams in their own conference three times (21 or 24 games in the west, 24 games in the east).

The remaining games of the season are inter-conference play (32 in the west, 30 in the east), allowing every team in the league to play every other team twice. One Western Conference exception is that one team from each division plays one less game inside Division and one more game inside Conference but outside their Division. Teams rotate every season. The schedule is structured so that every NHL team plays in every arena at least once per season.

The NBA follows a schedule similar to the NHL.

The NFL 16 game season is a home and away against teams in your division, and the balance against teams in your conference. One division each year plays games against teams in teh other conference,

Majro League Baseball is set up in three or four game series totaling 162 games. Each team plays 24 divisional series, 20 inter-divisional series, 8 inter-league series.

There are a number of software developers who have created complex programs to do this. Here’s one example (of many) link

All of the different software packages take into account the following – for any sport :

1) how many games in a season?
2) how often should teams play each other?
3) the divisional or regional structures for that sport
4) build in travel time or day off when flying west to east
5) special days (Yankees are always at home on July 4)
6) intra-division rivalries

and so on,.

The software devises the schedule, and then a human goes over it to make sure it is “sane”

I assume that people who work for the league are responsible for coming up with schedules in accordance with league rules.