Before the ceremony, he held bilateral meetings with the king of Spain and the presidents of Argentina, Ecuador, Chile, Paraguay and Panama. Also attending was Gianni Infantino, the embattled head of soccer's world governing body FIFA, while the U.S. sent a delegation headed by acting Attorney General Todd Blanche.
De La Espriella has blamed Petro, who has not recognized the new president's victory, for an expansion of armed groups, and narrowly defeated Petro ally, leftist Senator Ivan Cepeda, in the runoff. Cepeda led a morning march in Barranquilla on Friday, where he told demonstrators that the country's opposition will work to defend democracy and called for peaceful civil disobedience.
Investors have welcomed De La Espriella's market-friendly agenda, but expectations for rapid change are tempered by fiscal constraints and high public debt.
The head of the stock exchange has called for simpler participation by foreign and retail investors, lower transaction costs, eliminating dividend taxes and increasing Ecopetrol's publicly traded shares to 20%. Oil and mining guilds are optimistic but say changes must come quickly if Colombia is to ramp up gas production and meet other pressing needs.
The new administration is likely to focus its first 100 days on steps that De La Espriella can take directly, consulting firm Colombia Risk Analysis said in a report on Thursday.
"Security and anti-corruption efforts will likely serve as the most visible pillars of early momentum, though largely through workarounds and partial measures rather than full-scale execution," the report said. "Markets are likely to respond favorably in the short term (reflected in peso appreciation), but tax simplification and wealth tax elimination will likely reduce state revenue just as new spending needs emerge, especially if Colombians believe there's a rollback of benefits from the Petro administration."
De La Espriella has leaned heavily on Vice President-elect Jose Manuel Restrepo, a former finance minister who traveled to Washington to meet with Secretary of State Marco Rubio.
Other cabinet picks include Omar Bula, a former World Food Program official turned United Nations critic, as foreign minister; retired Major General Jorge Eduardo Mora as defense minister; electrical engineer Maria Arboleda as energy minister; and Miguel Gomez as finance minister.
Gomez has said the fiscal deficit stands at 7% to 8% of GDP, above outgoing government figures, and that the new administration will present a growth-focused tax reform.