He was the top ranked student in the 1958 graduating class at Boston Technical High School in Massachusetts.

He matriculated at the Rensselaer Polytechnic Institute in Troy, New York, where he was admitted to the Zeta Psi fraternity, graduating in 1962 with a Bachelor of Science degree in electrical engineering.

[1][2] Gajarsa was nominated by President Bill Clinton on January 7, 1997, to a seat on the United States Court of Appeals for the Federal Circuit vacated by Judge Helen W. Nies.

On November 3, 2010, Rensselaer Polytechnic Institute announced that Gajarsa would replace Samuel F. Heffner as Chairman of the Board at the start of 2011.

In the fall of 2012, Gajarsa joined the University of New Hampshire School of Law as its first Distinguished Jurist-in-Residence at the Franklin Pierce Center for Intellectual Property.