Baines grew up at 1 Jefferson Street in Manchester. He earned his bachelor's degree in music education from Saint Anselm College in Manchester, New Hampshire in 1968. He earned his master's in school administration in 1976 from Rivier College; he has done additional graduate study at the University of New Hampshire. He married his wife, Maureen, in 1974.
From 1968 to 1977 he was first a music teacher in a Hudson, New Hampshire high school before becoming assistant principal in the same school. 1980 saw Baines become principal of Manchester High School West, a position he was to hold until 1999, when he became mayor.
Baines is father of three children in their twenties, Timothy, Christina, and Catherine (b. 1985). Since 2004, he is grandfather of Jacob Miller (son of Christina and Michael Miller).
On July 21, 2006, Baines underwent surgery at Elliot Hospital in Manchester to remove a blockage in his colon. It was later revealed to have been a cancerous growth.
He has served on the board of directors for the National Association of Secondary School Principals and is currently a trustee and executive in residence at Southern New Hampshire University. In June of 2007 Baines was named interim president of Chester College of New England a position he is slated to hold for one year while the college searches for a replacement for former college president William Nevious .
Baines served two terms on the Manchester Board of Schools Committee in the early 1970s. He was a member of the 39th Army Band, New Hampshire National Guard from 1970 to 1976, and was awarded the New Hampshire Principal of the Year in 1990. 1996 saw him receive the Educator of the Year award from the Manchester Chamber of Commerce. In 2004 and 2005, he was named one of New Hampshire's "Ten Most Powerful People" by Business NH Magazine. As noted above, he was elected mayor of the city of Manchester in 1999, and reelected in 2001 and 2003. He was defeated in 2005.
On May 11, 2007, a New Hampshire Union Leader blog reported that Baines said he will not seek elected office again.
