Dan grew up in Oak Lawn, in the Southwest suburbs of Chicago, the son of immigrants.

His father, Danny grew up on a farm in County Kerry, in Ireland, as 14 out of 15 kids. His mother, Lucy grew up in London during World War II, during the Blitz. They were married in England and immigrated to America in 1957. 

Dan attended St. Gerald Grammar school in Oak Lawn and St. Laurence High School in Burbank. There, he attended honors classes and played on the varsity football team. He graduated from the University of Illinois in Champaign with a Bachelor's degree in Economics and double minors in Political Science and History. He received his law degree from Chicago Kent College of Law. 

He met his wife, Margo, at a program they both participated in for inner city kids in Chicago. Dan worked in a small law practice in New Lenox, and after a few years moved on to work as an attorney for Al Salvi and Associates in Waukegan. During the time that Dan worked there, Al Salvi ran for U.S. Senate, defeating Lt. Governor Bob Kustra in the primary, but losing to Dick Durbin in the general election.

In 1998, Dan started his own practice, and has practiced on his own ever since. He and Margo have three children: Kevin who's 8, Vivian, 4 and Sean 2.

Dan has served as the President of his neighborhood association, and has taught classes in real estate at the College of Lake County. He's active in the Cubs Scouts and teaches religious education to local children in the area. He and his wife currently volunteer their time at the VA Hospital in North Chicago and at Winchester House in Libertyville.

Dan is a member of the Lake County Bar Association and the Illinois Bar Association.