Modern English is a flexible language, and it’s becoming more so with each passing year. Today’s acceptable grammar is significantly more casual than the usage I learned as the frequent target of my sophomore English teacher’s red pen.
I’ve relaxed my standards with the times, but there are a few places where I believe it makes sense to hold the line. And one of those places is the use of the phrase “more importantly.” It’s one you’ll see frequently, and in nearly every instance, what the writer should have used is “more important.”
That’s not just because the latter is shorter. “More important” functions as an adjective, while “more importantly” is essentially an adverb. (I’m no grammarian, but if I were, I’d have fancier words for each version. Please bear with my ignorance.)
When you write “More important, Bill supports the company’s objectives,” you’re saying that Bill’s support of said objectives is the most important thing you need to know about Bill in this context. That’s what you wanted to say. If you instead write “More importantly, Bill supports the company’s objectives,” you shift the focus to how Bill goes about expressing his support. When someone acts “importantly,” it generally means they behave in a showy, pompous manner. If Bill is acting more importantly, it conjures images of him prancing around the conference room with his nose pointed skyward.
There’s a lot of debate about “more importantly” vs. “more important,” and some grammarians think that making a distinction is actually an example of acting more importantly. I disagree. Adjectives and adverbs each serve their roles, and 99 times out of 100, people who use “more importantly” are trying to make it work as an adjective. So if you simply delete the “ly,” you’ll be correct 99 percent of the time.