Note: I don't include the information from the movies, only the main and important information given in T:SCC Season 1. Please post if you have better pictures and more information.

Main Characters.

Sarah Connor.

Played by: Lena Headey.
Character & Plot Connections:
John Connor's mother. Kyle Reese's ex-lover. Charley Dixon's ex-fiancé. Ex-target with Andy Goode. Ally with Cameron Phillips and Derek Reese. Enemy with Cromartie and James Ellison.
Other info:
Mother of the resistance, responsible for raising John Connor and teaching him in the ways of war. Seen as a deranged fugitive by the authorities, who do not believe her story about the terminators. Determined to prevent Skynet's birth. Avoided death by cancer in 2005 by travelling to 2007. Forced to use different allies and move to various places. Destroyed ''The Turk'' by setting Andy Goode's house on fire. Tried to use John Connor's virus on ARTIE with Derek Reese but failed.
More info.

John Connor.

Played by: Thomas Dekker.
Character & Plot Connections:
Sarah Connor and Kyle Reese's Son. Protected by Cameron Phillips. Have some love interest in Cameron Phillips. Derek Reese's Nephew. Enemy with Cromartie and James Ellison.
Other info:
The future leader of the human resistance. Determined to prevent Skynet's birth. Forced to use different allies and move to various places. Creates a virus to corrupt ARTIE but Sarah Connor and Derek Reese failed to. Hacks Vick Chamberlain's CPU chip. Uses Cameron Phillip's CPU chip to corrupt ARTIE with Derek Reese.
More info.

Cameron Phillips (unknown model).

Played by: Summer Glau.
Mission:
Protect John Connor from being assassinated.
Character & Plot Connections:
John Connor's protector. Ally with Sarah Connor. Known to be the last to talk to Jordan Cowan, subsequently meeting with Mr. Harris. Freed Derek Reese and knew him before in the future. Destroyed Vick Chamberlain (T-888) and took one CPU chip. Blown up in a jeep by Sarkissian's car bomb.
Other info:
A reprogrammed terminator that was sent from the year 2027. Known to be created by Skynet outside the blast doors in the military bomb shelter after Judgement Day. Realistic advanced cyborg that is the most lethal and convincing infiltrator. Mimic human mannerisms better than the T-800 model, colour vision, and consume food. Used her CPU chip to corrupt ARTIE.
More info.

Agent James Ellison.

Played by: Richard T. Jones.
Character & Plot Connections:
Pursuing Sarah Connor as one of his FBI case. Questions Charley Dixon, George Lazlo, and Derek Reese. Saved by Sarah Connor from Dr. Peter Silberman's cabinet which was on fire. Pursues Cromartie (Agent Kester) but then his life was spared by Cromartie.
Other info:
FBI's top agent. Collects inexplicable evidence, he begins to question whether Sarah Connor is truly deranged.
More info.

Cromartie/Kester (T-888).

Played by: Owain Yeoman, David Kilde, Aaron James Cash, and Garret Dillahunt.
Mission:
Terminate John Connor and who ever prevents him from completing his mission.
Character & Plot Connections:
Uses and kills Dr. Flemming, who specializes in cellular growth. Dr. David Lyman helped him to build a new face of George Lazlo, then kills him. FBI impersonator (Agent Kester). Questions Charley Dixon. Tracks down by James Ellison but eventually Cromartie saves his life for future reasons.
Other info:
Destroyed by Sarah Connor however uses new biological covering for repairs and for a new identity.
More info.

Supporting Characters.

Andy Goode. (Deceased).

Played by: Brendan Hines.
Character & Plot Connections:
An assistant to Miles Dyson. Romantic interest in Sarah Connor. Killed by Derek Reese after ''The Turk 2'' lost the military contact against a Japanese rival computer, fearing that it might become Skynet. Friends with the resistances in the future.
Other info:
Caltech dropout who interned with Cyberdyne Systems. Has a job in a phone shop. Creator of an advanced artificial intelligence chess playing program, "The Turk" and ''The Turk 2''. Future Andy Goode renames himself as William Wisher.

Barbara Chamberlain. (Deceased).

Played by: Karina Logue.
Character & Plot Connections:
Vick Chamberlain's wife. ARTIE was opposed by Jessica Peck. Does not know her husband was a terminator after her husband's car accident, until she was killed by Vick Chamberlain.
Other info:
La Angeles city manager. Creator of ARTIE that led to the creation of Skynet. ARTIE is Automated Real-time Traffic Information Exchange.

Carlos Selceda.

Played by: Jesse Garcia.
Character & Plot Connections:
Enrique Selceda's nephew. Helped the Connors to receive their new identity (Baum). Has a gang which was killed by Sarkissian's gang.
Other info:
Purveyor of forged documents and continuing his family business.

Carter (unknown terminator).

Played by: Brian Bloom.
Mission:
Obtain and secure containers of coltan metal (a substance used in the endoskeletons of terminators) in the military bomb shelter. For the creation of terminators in the future.
Character & Plot Connections:
Hires and kills human personnels. Cameron and the Connors locked it in an military bomb shelter, and drove the truck with the containers of coltan metal into the ocean.
Other info:
Locked inside the military bomb shelter. Failed his mission.

Charley Dixon.

Played by: Dean Winters.
Character & Plot Connections:
Sarah's ex-fiancé. Husband of Michelle Dixon. Saved Derek's life. Told James Ellison about Sarah Connor when she went missing, which alerted Cromartie. Enemy with Agent Kester and James Ellison.
Other info:
Paramedic and engaged briefly with Sarah Connor for 6 months.

Cheri Westin.

Played by: Kristina Apgar.
Character & Plot Connections:
John's chemistry partner and classmate.
Other info:
Seems troubled and shuns everyone who attempts to befriend her. Morris revealed to John Connor that she may have a dysfunctional life after an unknown incident at the last school she attended.

Chola.

Played by: Sabrina Perez.
Character & Plot Connections:
Associate of Carlos. Ally with the Connors and Cameron Phillips.
Other info:
Known to be muted.

Daniel Dyson.

Played by: Shawn Prince.
Character & Plot Connections:
Son of Miles and Tarissa Dyson.
Other info:
N/A.

Derek Thomas Dekker.

Played by: Brian Austin Green. Ryan Kelley (Young Derek Reese).
Character & Plot Connections:
Older brother of Kyle Reese and biological uncle of John. One of the four resistance fighters which was sent by John Connor to the year 2007 from 2027. Spied on Andy Goode. Enemy with James Ellison and all terminators. The Connors and Charley Dixon saved his life after T-888 shot him.
Other info:
Resistance fighter which is to secure finance and other resources and to eliminate Skynet by helping the Connors to prevent anything leading to Skynet. Branded with a barcode by a terminator in a Skynet war camp. Witnessed the launch of missiles during Judgement Day when playing baseball in the yard. Determined to find and help the Connors find ''The Turk 2'' and destroy it.
More info.

Dmitri Shipkov. (Deceased).

Played by: Mark Ivanir.
Character & Plot Connections:
Brother of Maria Shipkov. Associate of Andy Goode. Provided the where-abouts of ''The Turk 2'' for Connors and Cameron. Killed by Russian gangsters.
Other info:
Chess master. Speaks Russian.

Enrique Selceda. (Deceased).

Played by: Tony Amendola.
Character & Plot Connections:
Past associate of Sarah Connor. Killed by Cameron Phillips.
Other info:
Provided the Connors firearms (events of Terminator 2). Retired expert at forging identities, his nephew has taken his family business. Killed as he was suspected to be a traitor.

George Lazlo. (Deceased).

Played by: Garret Dillahunt.
Character & Plot Connections:
Suspect of James Ellison. Cromartie used his identity. Killed by Cromartie.
Other info:
Actor.

Agent Greta Simpson. (Deceased).

Played by: Catherine Dent.
Character & Plot Connections:
FBI coworker of James Ellison. Doubts James Ellison's crusade to find Sarah Connor will lead to anything. Killed by Cromartie.
Other info:
N/A.

Jordan Cowan. (Deceased).

Played by: Alessandra Toreson.
Character & Plot Connections:
Sexual liaison with Mr. Harris. Classmate of John Connor and Cameron Phillips. Last talked to Cameron Phillips in the toilets. John Connor tried to save her life but Cameron Phillips stopped him.
Other info:
School cheerleader. Upset over graffiti on a classroom door. She was ashamed and then suicided.

Mr. Harris.

Played by: Neil Hopkins.
Character & Plot Connections: Sexual liaison with Jordan Cowan. Had a meeting with Cameron Phillips.
Other info:
School guidance counselor.

Michelle Dixon.

Played by: Sonya Walger.
Character & Plot Connections:
Wife of Charley Dixon. Met Agent Kester when questioning with Charley Dixon.
Other info:
Nurse. Possibly meet Charley Dixon at the hospital.

Miles Bennett Dyson. (Deceased).

Played by: Phil Morris.
Character & Plot Connections:
Agent Ellison showed the newspaper headline to Charley Dixon. Falsely known to be blown up by Sarah Connor.
Other info:
Original inventor of the neural-net processor which would lead to the development of Skynet. Killed however one of his assistants, Andy Goode, continued his work.

Kyle Reese. (Deceased).

Played by: Jonathan Jackson. Skyler Gisondo (Young Kyle Reese).
Character & Plot Connections:
Brother of Derek Reese. Father of John Connor. Protector of Sarah Connor.
Other info:
Resistance fighter who did not return from a top-secret mission, which he was known to be sent back to 1984 to protect to Sarah Connor (events of The Terminator).

Maria Shipkov. (Deceased).

Played by: Angela Gots.
Character & Plot Connections:
Sister of Dmitri Shipkov. Taught Cameron Phillips ballet and provided the where-abouts of her brother. Questioned and killed by Russian gangsters.
Other info:
Ballet teacher. Speaks Russian.

Morris.

Played by: Luis Chávez.
Character & Plot Connections:
Known to be John Connor's best friend. Classmate of John Connor and Cameron Phillips. Unpopular with some of his Latino peers. Attracted to Cameron.
Other info:
Worked as a car mechanic with John Connor. Secures a prom date from Cameron after John Connor prompts her.

Dr. Peter Silberman.

Played by: Bruce Davison
Character & Plot Connections:
Psychiatrist of Sarah Connor. James Ellison met him for questioning Sarah Connor and Vick Chamberlain's hand.
Other info:
Lives in a cabinet in the mountains. Believed in Sarah Connor's tale of apocalypse coming, therefore now locked up in Pescadero State Hospital.

Resistance Fighters (not including Derek Reese).

Timms, Sayles and Sumner. (Deceased).
Played by: Edoardo Ballerini, Jonathon Sadowski and Andre Royo, respectively.
Character & Plot Connections:
Compatriot of Derek Reese. Vick Chamberlain killed them in their apartment block.
Other info:
Resistance fighter which is to secure finance and other resources and to eliminate Skynet.

Sarkissian.

Played by: James Urbaniak. Craig Fairbrass (Impersonator). (Deceased).
Character & Plot Connections:
Associate of Dmitri Shipkov. The impersonator was killed by Derek Reese as he held John Connor as hostage. Ignited a car bomb in a jeep with Cameron Phillips inside. Blackmail the Connors for $2 million and threaten to expose them to the FBI.
Other info:
Works out of Cafe Wi-fi'd. Owner of ''The Turk 2''.

Agent Stewart.

Played by: Lee Thompson Young.
Character & Plot Connections:
FBI coworker of James Ellison and Greta Simpson.
Other info:
Objects James Ellison ideas on the case (the Connors).

T-600.

Played by: N/A
Character & Plot Connections:
Captured resistance fighters and lead them into a mysterious room.
Other info:
Terminator. Covered with rubber skin. Possibly a worker for Skynet.

Tarissa Dyson.

Played by: Charlayne Woodard.
Character & Plot Connections:
Widow of Miles Dyson and son of Daniel Dyson.
Other info:
Provided information on Miles Dyson's assistants and Andy Goode.

Vick Chamberlain (T-888). (Terminated).

Played by: Matt McColm.
Mission:
Eliminate resistance fighters including Derek Reese. Ensure the creation of ARTIE and Skynet.
Character & Plot Connections:
Terminated and replaced the real Barbara Chamberlain's husband. Kills all the resistance fighters except for Derek Reese. Kills Jessica Peck who threatened Barbara Chamberlain in creating ARTIE. Cameron took one of his three CPU chips and now is being used by John Connor.
Other info:
Left hand broke off during a fight against Cameron Phillips. Failed his mission to kill Derek Reese. Ability to connect to other computers.

Unknown terminator.

Played by: N/A.
Mission:
Terminate John Connor.
Character & Plot Connections:
N/A.
Other info:
Appeared in Sarah Connor's dream.

All characters and information.
Terminator Wiki.