Trolleybus service was inaugurated on 31 December 1952, as the country's second trolleybus system, after one that had opened in the capital, Santiago, in 1947.
 The Santiago system closed in 1978, and a second system that opened there in 1991 lasted only until 1994.

Trolleybuses replaced Valparaíso's last tram (streetcar) service, which had been introduced in 1863 as a horse-drawn street railway, one of the first in South America, and been converted to electric trams in 1904.
The last tram ran on 30 December 1952, and trolleybus service began the following day, on a route connecting Barón with Plaza Victoria.
 Only eight days later, on 7 January 1953, the route was extended from Plaza Victoria to Aduana.
 The eastern half of this first Barón–Aduana route followed Avenida Pedro Montt, but a second route connecting the same two termini but following Avenida Colón was introduced in February 1953.
 The western half of both routes was identical.
 The Avenida Colón route has remained in operation to the present day.

For many years, the Santiago and Valparaíso trolleybus systems were owned by the national government.
 Their original operator was the Empresa Nacional de Transportes (ENT), which had taken over the tram systems in both  cities in 1945.
 ENT was reorganized on 2 May 1953 as a new government agency, Empresa de Transportes Colectivos del Estado (ETCE), which then ran the system for the next 28 years.
 Both cities' systems used vehicles built by the American  manufacturer, Pullman-Standard.
 For Valparaíso, ENT had purchased 30 new trolleybuses from Pullman.
 Although Pullman – better known for its railway coaches – was a major U.S. builder of trolleybuses, manufacturing more than 2,000 in total, the 30 for Valparaíso were the very last trolleybuses the company ever built.
They were built in October and November 1952.

ETCE's Santiago system had a fleet of 100 Pullman trolleybuses (801–900), built in 1946 (the first six), 1947 and 1948, expanded in 1953 by the acquisition of 100 trolleybuses supplied by the French company, Vétra (numbered 901–1000).
 In 1954, ETCE transferred 39 of the Santiago Pullmans to Valparaíso, for use on a new 10 km (6.2-mile) interurban route to Viña del Mar.  Trolleybus service to Viña del Mar was inaugurated on 7 December 1959.
 However, the interurban service lasted less than five years, having already been abandoned by 1964, leaving trolleybuses in operation only within Valparaíso thereafter.

After the 1973 military coup, the new Pinochet administration reduced funding for government-run public transit, and the two trolleybus systems both deteriorated quickly.
 ETCE abandoned its Santiago trolleybus system in the latter half of 1978.
The Vetra trolleybuses had been less reliable and had all been scrapped by this time, but ETCE  transferred its remaining Santiago Pullman trolleybuses to Valparaíso,  where some were placed in service and the remainder provided a supply of parts to keep the others running.

The Valparaíso system struggled to maintain its now-elderly vehicles and infrastructure with limited funds, but eventually succumbed, closing on 30 November 1981.
 However, a group of local businessmen interested in reviving the trolleybus service soon acquired the assets of the now-dissolved Empresa de Transportes del Estado.
On 26 April 1982 they formed a new company whose name intentionally used the same initials, Empresa de Transportes Colectivos Eléctricos, Limitada (Electric Public Transport Company, Ltd.) (ETCE, again), and within two weeks had restored the service, using the same vehicles.
Service continued to follow two routes, both connecting Barón with Aduana but alternatively via either Avenida Colón or Avenida Pedro Montt.
 The routes were not numbered.
Trolleybus service was inaugurated on 31 December 1952, as the country's second trolleybus system, after one that had opened in the capital, Santiago, in 1947.  The Santiago system closed in 1978, and a second system that opened there in 1991 lasted only until 1994.
Trolleybuses replaced Valparaíso's last tram (streetcar) service, which had been introduced in 1863 as a horse-drawn street railway, one of the first in South America, and been converted to electric trams in 1904. The last tram ran on 30 December 1952, and trolleybus service began the following day, on a route connecting Barón with Plaza Victoria.  Only eight days later, on 7 January 1953, the route was extended from Plaza Victoria to Aduana.  The eastern half of this first Barón–Aduana route followed Avenida Pedro Montt, but a second route connecting the same two termini but following Avenida Colón was introduced in February 1953.  The western half of both routes was identical.  The Avenida Colón route has remained in operation to the present day.
For many years, the Santiago and Valparaíso trolleybus systems were owned by the national government.  Their original operator was the Empresa Nacional de Transportes (ENT), which had taken over the tram systems in both  cities in 1945.  ENT was reorganized on 2 May 1953 as a new government agency, Empresa de Transportes Colectivos del Estado (ETCE), which then ran the system for the next 28 years.  Both cities' systems used vehicles built by the American  manufacturer, Pullman-Standard.  For Valparaíso, ENT had purchased 30 new trolleybuses from Pullman.  Although Pullman – better known for its railway coaches – was a major U.S. builder of trolleybuses, manufacturing more than 2,000 in total, the 30 for Valparaíso were the very last trolleybuses the company ever built. They were built in October and November 1952.
ETCE's Santiago system had a fleet of 100 Pullman trolleybuses (801–900), built in 1946 (the first six), 1947 and 1948, expanded in 1953 by the acquisition of 100 trolleybuses supplied by the French company, Vétra (numbered 901–1000).  In 1954, ETCE transferred 39 of the Santiago Pullmans to Valparaíso, for use on a new 10 km (6.2-mile) interurban route to Viña del Mar.  Trolleybus service to Viña del Mar was inaugurated on 7 December 1959.  However, the interurban service lasted less than five years, having already been abandoned by 1964, leaving trolleybuses in operation only within Valparaíso thereafter.
After the 1973 military coup, the new Pinochet administration reduced funding for government-run public transit, and the two trolleybus systems both deteriorated quickly.  ETCE abandoned its Santiago trolleybus system in the latter half of 1978. The Vetra trolleybuses had been less reliable and had all been scrapped by this time, but ETCE  transferred its remaining Santiago Pullman trolleybuses to Valparaíso,  where some were placed in service and the remainder provided a supply of parts to keep the others running.
The Valparaíso system struggled to maintain its now-elderly vehicles and infrastructure with limited funds, but eventually succumbed, closing on 30 November 1981.  However, a group of local businessmen interested in reviving the trolleybus service soon acquired the assets of the now-dissolved Empresa de Transportes del Estado. On 26 April 1982 they formed a new company whose name intentionally used the same initials, Empresa de Transportes Colectivos Eléctricos, Limitada (Electric Public Transport Company, Ltd.) (ETCE, again), and within two weeks had restored the service, using the same vehicles. Service continued to follow two routes, both connecting Barón with Aduana but alternatively via either Avenida Colón or Avenida Pedro Montt.  The routes were not numbered.
Trolleybuses in Valparaíso