Although he grew up in Vancouver, Yallop played professional football for nearly 20 years in England and the United States. In 1983, at age 19, Yallop signed a professional contract with Ipswich Town, for whom he would play 385 games (in all competitions), scoring 8 goals. He saw their relegation from the First Division in 1986, but stayed loyal to the club and helped them win promotion six years later to the new FA Premier League, where they stayed for three years before being relegated once again. Yallop remained at the club for a further season after this.
In the later years of his Ipswich career, he played alongside fellow Canadian Craig Forrest.
One of his eight goals for the Tractor Boys came in February 1993 as they beat Premier League title favourites Manchester United 2–1 at Portman Road, a result which saw Ipswich occupy fourth place in the league and spark hopes of a late run to the title, but instead a slump in form followed and Ipswich finished 16th.
After a lengthy career in England, Yallop returned to North America in 1996, when he signed with Major League Soccer and was drafted 57th overall by the Tampa Bay Mutiny in the MLS Inaugural Player Draft. After three seasons with the Mutiny, in which he started practically every game, Yallop retired from professional football at the end of the 1998 season.
Missing out on Canada's only World Cup participation in 1986, Yallop only made his debut for Canada at 26 years of age in a May 1990 North American Championship match against the United States. Since this game strangely was not official his real debut came a few days later in the same tournament against Mexico. He earned 52 caps, scoring no goals. He has represented Canada in 27 FIFA World Cup qualification matches. His final international was a November 1997 World Cup qualification match against Costa Rica.
Yallop began his coaching career in 1998 with the US Project-40 team, taking the team on a 5 game tour of England. Following the tour, he became assistant coach for the Tampa Bay Mutiny. In 2000 he became chief assistant coach for D.C. United under Thomas Rongen.
The Galaxy failed to qualify for the play-offs in 2007, although Yallop has been defended for his part in that, with San Jose forward Alan Gordon, who played on the '07 Galaxy team stating "It had nothing to do with Frank. We had 11 guys come in and out of there in a couple months. We had no team chemistry. We had a bunch of individuals who were trying to hang on and make the best of it." On 4 November 2007 it was revealed that Yallop was being bought out of his contract with the Galaxy to become the head coach of the San Jose Earthquakes once again for the 2008 season, with DutchmanRuud Gullit taking his place. Yallop and the Earthquakes parted ways on 7 June 2013.