Gladstone graduated from Kent School in 1960 where he began his rowing career. He then attended Syracuse University where he continued to row and graduated with a bachelor's degree in American literature. He is the son of Henry Gladstone, a renowned radio announcer in the 1950s and 1960s in New York City.
Gladstone began coaching in 1966, directing the Princeton University freshmen to a pair of silver medals at the Intercollegiate Rowing Association regatta, also known as the IRA. Gladstone then took over as varsity lightweight coach at Harvard in 1970. His Harvard crews were undefeated for four straight seasons. They won four straight Eastern Sprints championships and, in 1971, the Thames Challenge Cup and Wyfold Challenge Cup at the Henley Royal Regatta in England.
In 1973, he was appointed as head coach of the Cal varsity crew team. He also coached the 1973 U.S. National team. During his tenure at Cal from 1973–80, Gladstone's Bears had three undefeated dual-race seasons, an IRA title in 1976, yet only one Pac-10 championship in 1979.
Gladstone retired after the 1980 season and coached the Cal Alumni for one race in 1981—winning the San Diego Crew Classic. He then decided to coach rowing again and was approached by Brown University.
Gladstone coached Brown from 1982–94. At Brown, Gladstone crews amassed four Eastern Sprints championships, five IRA championships and two National Collegiate Rowing Championship titles. In both 1993 and '94, the Brown varsity crew completed the "triple crown" with victories in each of these regattas – a feat that had never before been accomplished. In Gladstone's final season at Brown, the men's crew went undefeated as a program at all levels of competition. Many of Gladstone's athletes at Brown became members of the national teams for the USA and for other countries. Following the 1994 season, Gladstone retired from coaching rowing for the second time.
Upon retiring, Gladstone helped found Resolute Racing Shells, where he was president and director of marketing. However, Gladstone returned to coaching crew at Cal beginning with the 1997 season.
In his first two years back, his varsity squads finished third at the IRA. In 1999, Gladstone's varsity boat ended Cal's 23-year IRA championship drought. Cal then went on to capture four straight IRA varsity titles from 1999 through 2002 and was undefeated for three straight years. His assistant coach in charge of the freshman squad at this time was rowing coach Craig Amerkhanian (who later went on to a career at Stanford University). The majority of Gladstone and Amerkhanian's oarsmen from those years were members of the national team for either the USA or some other country.
After his return to Cal, Gladstone's varsity boat won seven Pac-10 championships. In addition, they won seven straight San Diego Crew Classics, 1999–2005, and four straight Windemere Collegiate Crew Classics, 2003–2006.
In 2001, Gladstone was named Director of the Intercollegiate Athletic Department at Cal from which he resigned from in 2004 to focus solely on his job as the head coach of Cal men's crew. Gladstone's tenure as athletic director included the hiring football head coach Jeff Tedford.
After the 2008 rowing season, Gladstone retired from collegiate coaching and accepted a job with the California Rowing Club, which is housed on the same property as Cal but in adjacent boathouses.
In 2010, Gladstone left the CRC to assume the head coaching position for the Yale University heavyweight men. Since then he has brought the program at Yale back in the national spotlight. His efforts began to bear fruit during the 2014-2015 season, with a first-place finish at Eastern Sprints (the first for Yale since 1982), a win over Harvard in their annual head-to-head race (the first since 2007), and a win over five-time national champion University of Washington at Henley Royal Regatta in the final of the Ladies' Challenge Plate. Yale followed up these results with a first-place finish at the 2015 Head of the Charles Regatta in the regatta's marquee event, the Men's Championship Eights. In 2017, Yale went on to capture its first IRA varsity title by defeating the University of Washington at Lake Natoma by 0.069 seconds.
Gladstone has served on the Board of Directors of the National Association of Amateur Oarsmen and has also been a member of the Men's Olympic Rowing Committee.
Including his tenure at Cal and Brown, Gladstone's boats won 12 IRA titles in the varsity event, trailing only Charles E. Courtney of Cornell who coached from 1883 to 1920, who amassed 14. His six IRA victories at Cal also ties him with the legendary Carroll M. "Ky" Ebright for most victories by a Cal coach. During his career at Harvard, Cal and Brown, Gladstone's first boat has officially won the conference championship a remarkable 16 times.
Lightweight Varsity BoatEastern Sprints Champions 1969, 1970, 1971 and 1972
Heavyweight Varsity BoatEastern Sprints Champions 1982, 1984, 1987, 1993, 1994, 2015, 2016, and 2017
Pac-10 Champions 1979, 1998, 1999, 2000, 2001, 2002, 2005 and 2006
IRA Champions 1976, 1983, 1986, 1987, 1993, 1994, 1999, 2000, 2001, 2002, 2006, and 2017
National Collegiate Rowing Championships 1993, 1994
San Diego Crew Classic 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2016
Head of the Charles Regatta, Men's Championship Eights, first place (2015)