I hear the phrase "in my wheelhouse" every day, often in business and news. For example, on September 18th, CNN reported (emphasis added):
Donald Trump stood sweating in a crowded gym, fielding questions from voters on agriculture fees, family court disputes and military base closures. The Republican front-runner was no longer in his wheelhouse.
What the heck is a wheelhouse, anyway?
According to my beloved Wordnik, there appear to be several definitions that may apply. These seem solid:
from Wiktionary, Creative Commons Attribution/Share-Alike License n. An enclosed compartment, on the deck of a vessel such as a fishing boat, from which it may be navigated; on a larger vessel it is the bridge or pilothouse n. A batter's power zone
It's All About Boats
If you've been on a boat large enough to have a wheel, you'll recall that there's typically a room enclosing that wheel. That's the wheelhouse. On the largest shipping vessels, it's an enormous room full of technical equipment for navigation—it's the command center.
On smaller vessels, the wheelhouse may not be fully enclosed, but it's still the command center, typically located with good lines of sight to both the vessel and the water surrounding it. Here's a recent example from Twitter (conveniently hashtagged #wheelhouse) showing the inside of a wheelhouse:
So when a captain is in his or her wheelhouse, that's a place of command and control. If you're in your wheelhouse, that's any situation in which you feel comfortable.
...And Baseball
The term "wheelhouse" appears to have entered common use through baseball. In baseball, a batter's "wheelhouse" is the part of a batter's strike zone in which he or she is most likely to hit a home run. It seems likely that the nautical form of "wheelhouse" was borrowed by baseball, becoming prominent in baseball writing starting in the 1950s.
From there, it takes only a bunt for the term to become embedded in American business-speak. Here's a Google Ngrams chart showing the growth of the term "wheelhouse" (in all forms, but we can surmise that at least some of this writing has to do with baseball) from 1920 through 2008:
Other Terms
According to an excellent Chicago Tribune article by Heidi Stevens from 2012, there are obvious options if you want to use a less jargon-y term instead of "wheelhouse":
"Whenever someone wants to say, 'We would be good at this,' or 'We have potential here,' they say, 'This is in our wheelhouse,'" [Bruce] Watson told us in a phone interview. "What they mean is, 'This is a promising area for expansion.'"
Now it's time to get back to my wheelhouse and hit 'em out of the park.