Schaeffer rose to fame with fellow actor/writer/director Donal Lardner Ward on the independent film, My Life's in Turnaround (1993), which was made in fifteen days for only $200,000. Schaeffer and Ward parlayed the film's success into Too Something (1995–1996), a short-lived sitcom that was briefly renamed New York Daze.

He signed on as a client of Creative Artists Agency and made a deal to direct the 1996 romantic comedy If Lucy Fell for a budget of $3.5 million for Columbia TriStar.

Schaeffer starred opposite model Amanda de Cadenet in the 1997 romantic drama Fall, about a cab driver who begins a passionate affair with a model he first met in his cab.

In 2000, he released the comedy Wirey Spindell, a semi-autobiographical tale. This was followed by the romantic comedy Never Again in 2001, starring Jill Clayburgh and Jeffrey Tambor, and Mind the Gap in 2004.

In 2008, Schaeffer debuted a reality television series on Showtime, also called, I Can't Believe I'm Still Single.

In 2009, Schaeffer and Jill Franklyn created the half-hour dramedy series Gravity for Starz. The series about people who have failed at suicide – originally titled Failure to Fly – stars Schaeffer along with Krysten Ritter, Ivan Sergei, Ving Rhames and Rachel Hunter. It began airing in April 2010 and on June 30, 2010, the show was cancelled.

In recent years Schaeffer has been writing an autobiographical blog, I Can't Believe I'm Still Single, about his relationships and ongoing search for love. Schaeffer has turned the blog into a book, I Can't Believe I'm Still Single – Sane, Slightly Neurotic (But in a Sane Way) Filmmaker into Good Yoga, Bad Reality TV, Too Much Chocolate, and a Little Kinky Sex Seeks Smart, Emotionally Evolved ... Oh Hell, At This Point Anyone Who'll Let Me Watch Football.