Mark was born in Chicago, under the care of Catholic Charities, and became a part of their foster care program. Ronald and Katherine LaFontaine took him into their care as foster parents when he was six months old and then adopted Mark when he was three. The LaFontaine family moved to Broward County in 1973, and settled in Deerfield Beach where Mark's father owned a small business and his mother worked as a librarian for the Broward County Public Library System.
Mark attended grade school at St. Ambrose Catholic School in Deerfield Beach, where he was an altar boy and lector, and excelled in sports and academics. He earned his Eagle Scout award from the Boy Scouts of America. from Troop 337 when he was 16, then became junior assistant scoutmaster and ultimately assistant scoutmaster. He graduated in 1985 from Deerfield Beach High School in the top 10 percent of his class. He was an Honor Student who received several awards, including a Congressional appointment to the Merchant Marine Academy from former Rep. E. Clay Shaw. Mark left the Academy early, but wanted to serve his country so he enlisted in the US Coast Guard. He served on the USCG Basswood WLB-388 in Guam for two years.
Upon his return to South Florida, Mark enrolled in Florida Metropolitan University, where he studied accounting. He received his Bachelors degree, graduated summa cum laude, and was the class valedictorian. He went on to earn his Masters degree in Taxation from Florida International University. Mark worked for several years as a staff accountant and at the Veterans Administration in Oakland Park before opening his own practice in 1999.
Mark's public profile was raised when he began to speak out against discrimination in Broward County. He became a leader in the movement to end the Boy Scouts' discriminatory practices against youth and parents who happen to be gay or lesbian. Mark became a national spokesperson in Scouting for All, which promotes change within the Boy Scouts organization.
Drawing together a diverse coalition including Parents and Friends of Lesbians and Gays (P-FLAG); Gay, Lesbian and Straight Education Network (GLSEN); and religious and mental health leaders Mark's effort led to several government and community organizations pulling their funding from the Boy Scouts - including Broward County, the Broward School Board, and United Way of Broward County. For standing up for fairness, the Boy Scouts retaliated against Mark by throwing him out of the National Eagle Scout Association - the first Eagle Scout to be banned from the organization.
Continuing his service to veterans, Mark is the national treasurer of U.S.A.n Veterans for Equal Rights (AVER), and is president of its Florida Gold Coast chapter, the largest in the country. AVER serves all veterans, with a special emphasis on the needs of gay, lesbian, bisexual and transgender vets, who often face specific obstacles.
Mark's diverse community involvement includes serving on the Board of Oakland Park Main Street, which is guiding the city's development; the Fort Lauderdale Audit Committee, which reviews the city's major expenditures; and the Dolphin Democrats, where he was treasurer.
Mark has received numerous awards for his work and service, including the GLCC Stars of the Rainbow for Male Role Model; the Dolphin Democrats Trailblazer Award; and an Appreciation Award from the Veterans Administration.