There are different schools of thought on just about every resume issue and this is one of the top debates. In a series of a dozen plus in-person and virtual resume workshops hosted by our team over the past four weeks, this was the top question that kept popping up.
As you're probably aware by now, the "1 vs 2 page" debate doesn't have a clear winner overall. Some recruiters and employers feel that short and sweet is best because recruiters and employers are too busy to read 2 pages; others swear that the 1-page resume is an outdated holdover from the days when you had to worry that the second page of your hardcopy resume would get lost in a sea of papers. Everyone agrees that everything on the page should be relevant, though.
Similarly, ATS systems sometimes prefer 2-page resumes because they're able to pack in more keywords overall, and they also tend to include more instances of the most important keywords. On the other hand, many ATS systems also prefer a document below a certain keyword count, so cramming in too much info can also hurt rather than help.
Everyone agrees that everything on the page should be relevant, though.
Some experts say 5 years is the point at which one can graduate to the 2-page resume, and recent research has shown that recruiters find 2-page resumes more helpful at all career levels because they tend to highlight more accomplishments and better show the candidate's potential vs. focusing primarily on daily responsibilities and skills that make it harder to differentiate one candidate from the next.
For college students, we think the 1-page length is generally the most appropriate. For working professionals, we think either can be appropriate. We acknowledge that there is a wide range of opinions and rationale, but no absolute "rule" that must be followed.