Lord Coe stressed his commitment to cracking down on drug cheats after being elected to the most powerful position in world athletics.
The former London 2012 chairman was voted in as the new president of the International Association of Athletics Federations, seeing off the challenge of Ukrainian Sergey Bubka in a vote at the IAAF Congress in Beijing on Wednesday.
The two-time Olympic 1500 metres champion, who was raised in Sheffield and is a former pupil of Tapton and Abbeydale Grange Schools, secured the support of the majority of the 207 IAAF member federations who voted, winning by 115 votes to 92.
Coe, who takes office at the end of the World Championships, which gets under way on Saturday, succeeds Lamine Diack, the 82-year-old from Senegal who has been president since 1999, and becomes only the sixth president in the IAAF's 103-year history.
The 58-year-old's elevation from vice-president, a post he has held since 2007, comes at a crucial time for the organisation, with allegations of mass doping and cover-ups threatening to ruin the already fragile reputation of the sport.
The Briton, who has been a staunch defender of the IAAF's anti-doping record, has pledged to set up an independent anti-doping agency for the sport.
He said: "There is a zero tolerance to the abuse of doping in my sport and I will maintain that to the very highest level of vigilance."
Coe declined to go into the details of how his anti-doping body would work, saying it was something he would discuss with his IAAF colleagues over the coming weeks.
But he did admit there was a perception that in-house drug testing created "conflicts" and "loopholes".
He added: "I have espoused the concept of an independent testing process. That isn't in any way to question the technical or the professional ability of our team in Monaco. They are world class at what they do, they are best in class at what they do and I won't bend a knee to anybody on that subject in defending their professional integrity.
"We do have to recognise that there is too broad a view that this is something, whether real or perceived, (where) there are conflicts and there are loopholes and I think an independent system is what we need to close down any thought that we are doing anything other than being entirely vigilant about that."
Coe has highlighted the need to overhaul the athletics calendar, introducing more 'street meets', increase commercial revenue, empower national federations and encourage young people into the sport.
But it is the fight against banned drugs which is set to be front and centre of his reign.
The IAAF has come under fierce attack amid allegations - which it vehemently denies - that it turned a blind eye to suspicious blood test results from hundreds of athletes and also blocked the publication of a report claiming a third of athletes at the 2011 World Championships in South Korea admitted doping.
Coe has been the most outspoken voice on the accusations the IAAF has ignored possible widespread drug use, calling them a "declaration of war" on the sport.
Despite the strong rebuttals, it is clear serious damage has been done, and is being done, to the credibility of the organisation and the sport as a whole, an issue which needs to be addressed urgently.
UK Athletics chairman Ed Warner backed Coe to tackle the doping problem head on.
He said: "If there's one person that I know will pursue cheats to all four corners of the earth it is Seb, who's been passionate about his anti-doping commitment over many years, from a competitor, through all his years as an administrator."
Paula Radcliffe added: "I think Seb is going to restore the credibility of anti-doping by investing more in it, making it independent and making sanctions tougher. Then he needs to be more transparent in just explaining how things work."
World Anti-Doping Agency president Craig Reedie said: "We look forward to a positive and strong relationship with the new president in his avowed plans to protect the rights of the clean athlete."
Coe, who received congratulations from the likes of Prime Minister David Cameron, has worked tirelessly to garner support from countries around the world during his campaign, travelling around 700,000 kilometres across the globe since Christmas.
"Delighted @sebcoe has been elected the new president of the IAAF - an outstanding athlete who delivered the brilliant London 2012 Olympics," Cameron wrote on Twitter.
Coe described his victory as the "second biggest and momentous occasion" of his life after the birth of his children, adding: "This for me is the pinnacle, it's my sport, it's my passion, it's the thing I always wanted to do."
Coe, whose other posts include chairman of the British Olympic Association, executive chairman of CSM Sport and Entertainment - a sports marketing outfit - and global advisor to Nike, said it was too soon to say whether he would have to scale back any of those roles.
The former Conservative Party MP said: "I made the point absolute unflinchingly (to the Congress) this morning, you have a president who will devote full-time attention to the management and the direction of the IAAF. I would not have thrown by hat into the ring if I felt that I would be short changing this organisation.
"How I combine that is something that I've always managed. My life has always been fairly complicated and very busy, I have a team dedicated to making sure that works. Anything I have to do to accommodate around the presidency of the federation I will do, but it's very early to give you a definite view of that."
Coe appeared riled when pushed on his links to Nike, saying: "I have only been at Nike since 1978, so that's a fairly new relationship and I've always managed so far to put that into the right space."
Bubka was re-elected as an IAAF vice-president at the Congress.